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The ungleich kubernetes infrastructure » History » Version 123

Nico Schottelius, 08/27/2022 04:49 PM

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h1. The ungleich kubernetes infrastructure and ungleich kubernetes manual
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{{toc}}
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h2. Status
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This document is **pre-production**.
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This document is to become the ungleich kubernetes infrastructure overview as well as the ungleich kubernetes manual.
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h2. k8s clusters
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| Cluster            | Purpose/Setup     | Maintainer | Master(s)                     | argo                                                   | v4 http proxy | last verified |
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| c0.k8s.ooo         | Dev               | -          | UNUSED                        |                                                        |               |    2021-10-05 |
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| c1.k8s.ooo         | retired           |            | -                             |                                                        |               |    2022-03-15 |
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| c2.k8s.ooo         | Dev p7 HW         | Nico       | server47 server53 server54    | "argo":https://argocd-server.argocd.svc.c2.k8s.ooo     |               |    2021-10-05 |
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| c3.k8s.ooo         | retired           | -          | -                             |                                                        |               |    2021-10-05 |
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| c4.k8s.ooo         | Dev2 p7 HW        | Jin-Guk    | server52 server53 server54    |                                                        |               |             - |
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| c5.k8s.ooo         | retired           |            | -                             |                                                        |               |    2022-03-15 |
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| c6.k8s.ooo         | Dev p6 VM Jin-Guk | Jin-Guk    |                               |                                                        |               |               |
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| [[p5.k8s.ooo]]     | production        |            | server34 server36 server38    | "argo":https://argocd-server.argocd.svc.p5.k8s.ooo     | -             |               |
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| [[p5-cow.k8s.ooo]] | production        | Nico       | server47 server51 server55    | "argo":https://argocd-server.argocd.svc.p5-cow.k8s.ooo |               |    2022-08-27 |
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| [[p6.k8s.ooo]]     | production        |            | server67 server69 server71    | "argo":https://argocd-server.argocd.svc.p6.k8s.ooo     | 147.78.194.13 |    2021-10-05 |
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| [[p10.k8s.ooo]]    | production        |            | server63 server65 server83    | "argo":https://argocd-server.argocd.svc.p10.k8s.ooo    | 147.78.194.12 |    2021-10-05 |
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| [[k8s.ge.nau.so]]  | development       |            | server107 server108 server109 | "argo":https://argocd-server.argocd.svc.k8s.ge.nau.so  |               |               |
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| [[dev.k8s.ooo]]    | development       |            | server110 server111 server112 | "argo":https://argocd-server.argocd.svc.dev.k8s.ooo    | -             |    2022-07-08 |
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h2. General architecture and components overview
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* All k8s clusters are IPv6 only
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* We use BGP peering to propagate podcidr and serviceCidr networks to our infrastructure
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* The main public testing repository is "ungleich-k8s":https://code.ungleich.ch/ungleich-public/ungleich-k8s
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** Private configurations are found in the **k8s-config** repository
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h3. Cluster types
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| **Type/Feature**            | **Development**                | **Production**         |
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| Min No. nodes               | 3 (1 master, 3 worker)         | 5 (3 master, 3 worker) |
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| Recommended minimum         | 4 (dedicated master, 3 worker) | 8 (3 master, 5 worker) |
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| Separation of control plane | optional                       | recommended            |
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| Persistent storage          | required                       | required               |
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| Number of storage monitors  | 3                              | 5                      |
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h2. General k8s operations
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h3. Cheat sheet / external great references
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* "kubectl cheatsheet":https://kubernetes.io/docs/reference/kubectl/cheatsheet/
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h3. Allowing to schedule work on the control plane / removing node taints
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* Mostly for single node / test / development clusters
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* Just remove the master taint as follows
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<pre>
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kubectl taint nodes --all node-role.kubernetes.io/master-
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kubectl taint nodes --all node-role.kubernetes.io/control-plane-
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</pre>
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You can check the node taints using @kubectl describe node ...@
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h3. Get the cluster admin.conf
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* On the masters of each cluster you can find the file @/etc/kubernetes/admin.conf@
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* To be able to administrate the cluster you can copy the admin.conf to your local machine
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* Multi cluster debugging can very easy if you name the config ~/cX-admin.conf (see example below)
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<pre>
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% scp root@server47.place7.ungleich.ch:/etc/kubernetes/admin.conf ~/c2-admin.conf
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% export KUBECONFIG=~/c2-admin.conf    
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% kubectl get nodes
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NAME       STATUS                     ROLES                  AGE   VERSION
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server47   Ready                      control-plane,master   82d   v1.22.0
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server48   Ready                      control-plane,master   82d   v1.22.0
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server49   Ready                      <none>                 82d   v1.22.0
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server50   Ready                      <none>                 82d   v1.22.0
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server59   Ready                      control-plane,master   82d   v1.22.0
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server60   Ready,SchedulingDisabled   <none>                 82d   v1.22.0
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server61   Ready                      <none>                 82d   v1.22.0
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server62   Ready                      <none>                 82d   v1.22.0               
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</pre>
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h3. Installing a new k8s cluster
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* Decide on the cluster name (usually *cX.k8s.ooo*), X counting upwards
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** Using pXX.k8s.ooo for production clusters of placeXX
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* Use cdist to configure the nodes with requirements like crio
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* Decide between single or multi node control plane setups (see below)
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** Single control plane suitable for development clusters
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Typical init procedure:
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* Single control plane: @kubeadm init --config bootstrap/XXX/kubeadm.yaml@
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* Multi control plane (HA): @kubeadm init --config bootstrap/XXX/kubeadm.yaml --upload-certs@
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h3. Deleting a pod that is hanging in terminating state
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<pre>
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kubectl delete pod <PODNAME> --grace-period=0 --force --namespace <NAMESPACE>
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</pre>
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(from https://stackoverflow.com/questions/35453792/pods-stuck-in-terminating-status)
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h3. Listing nodes of a cluster
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<pre>
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[15:05] bridge:~% kubectl get nodes
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NAME       STATUS   ROLES                  AGE   VERSION
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server22   Ready    <none>                 52d   v1.22.0
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server23   Ready    <none>                 52d   v1.22.2
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server24   Ready    <none>                 52d   v1.22.0
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server25   Ready    <none>                 52d   v1.22.0
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server26   Ready    <none>                 52d   v1.22.0
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server27   Ready    <none>                 52d   v1.22.0
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server63   Ready    control-plane,master   52d   v1.22.0
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server64   Ready    <none>                 52d   v1.22.0
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server65   Ready    control-plane,master   52d   v1.22.0
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server66   Ready    <none>                 52d   v1.22.0
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server83   Ready    control-plane,master   52d   v1.22.0
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server84   Ready    <none>                 52d   v1.22.0
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server85   Ready    <none>                 52d   v1.22.0
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server86   Ready    <none>                 52d   v1.22.0
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</pre>
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h3. Removing / draining a node
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Usually @kubectl drain server@ should do the job, but sometimes we need to be more aggressive:
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<pre>
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kubectl drain --delete-emptydir-data --ignore-daemonsets serverXX
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</pre>
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h3. Readding a node after draining
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<pre>
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kubectl uncordon serverXX
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</pre>
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h3. (Re-)joining worker nodes after creating the cluster
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* We need to have an up-to-date token
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* We use different join commands for the workers and control plane nodes
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Generating the join command on an existing control plane node:
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<pre>
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kubeadm token create --print-join-command
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</pre>
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h3. (Re-)joining control plane nodes after creating the cluster
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* We generate the token again
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* We upload the certificates
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* We need to combine/create the join command for the control plane node
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Example session:
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<pre>
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% kubeadm token create --print-join-command
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kubeadm join p10-api.k8s.ooo:6443 --token xmff4i.ABC --discovery-token-ca-cert-hash sha256:longhash 
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% kubeadm init phase upload-certs --upload-certs
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[upload-certs] Storing the certificates in Secret "kubeadm-certs" in the "kube-system" Namespace
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[upload-certs] Using certificate key:
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CERTKEY
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# Then we use these two outputs on the joining node:
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kubeadm join p10-api.k8s.ooo:6443 --token xmff4i.ABC --discovery-token-ca-cert-hash sha256:longhash --control-plane --certificate-key CERTKEY
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</pre>
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Commands to be used on a control plane node:
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<pre>
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kubeadm token create --print-join-command
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kubeadm init phase upload-certs --upload-certs
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</pre>
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Commands to be used on the joining node:
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<pre>
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JOINCOMMAND --control-plane --certificate-key CERTKEY
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</pre>
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SEE ALSO
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* https://stackoverflow.com/questions/63936268/how-to-generate-kubeadm-token-for-secondary-control-plane-nodes
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* https://blog.scottlowe.org/2019/08/15/reconstructing-the-join-command-for-kubeadm/
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h3. How to fix etcd does not start when rejoining a kubernetes cluster as a control plane
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If during the above step etcd does not come up, @kubeadm join@ can hang as follows:
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<pre>
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[control-plane] Creating static Pod manifest for "kube-apiserver"                                                              
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[control-plane] Creating static Pod manifest for "kube-controller-manager"                                                     
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[control-plane] Creating static Pod manifest for "kube-scheduler"                                                              
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[check-etcd] Checking that the etcd cluster is healthy                                                                         
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error execution phase check-etcd: etcd cluster is not healthy: failed to dial endpoint https://[2a0a:e5c0:10:1:225:b3ff:fe20:37
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8a]:2379 with maintenance client: context deadline exceeded                                                                    
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To see the stack trace of this error execute with --v=5 or higher         
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</pre>
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Then the problem is likely that the etcd server is still a member of the cluster. We first need to remove it from the etcd cluster and then the join works.
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To fix this we do:
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* Find a working etcd pod
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* Find the etcd members / member list
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* Remove the etcd member that we want to re-join the cluster
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<pre>
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# Find the etcd pods
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kubectl -n kube-system get pods -l component=etcd,tier=control-plane
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# Get the list of etcd servers with the member id 
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kubectl exec -n kube-system -ti ETCDPODNAME -- etcdctl --endpoints '[::1]:2379' --cacert /etc/kubernetes/pki/etcd/ca.crt --cert  /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.key member list
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# Remove the member
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kubectl exec -n kube-system -ti ETCDPODNAME -- etcdctl --endpoints '[::1]:2379' --cacert /etc/kubernetes/pki/etcd/ca.crt --cert  /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.key member remove MEMBERID
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</pre>
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Sample session:
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<pre>
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[10:48] line:~% kubectl -n kube-system get pods -l component=etcd,tier=control-plane
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NAME            READY   STATUS    RESTARTS     AGE
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etcd-server63   1/1     Running   0            3m11s
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etcd-server65   1/1     Running   3            7d2h
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etcd-server83   1/1     Running   8 (6d ago)   7d2h
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[10:48] line:~% kubectl exec -n kube-system -ti etcd-server65 -- etcdctl --endpoints '[::1]:2379' --cacert /etc/kubernetes/pki/etcd/ca.crt --cert  /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.key member list
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356891cd676df6e4, started, server65, https://[2a0a:e5c0:10:1:225:b3ff:fe20:375c]:2380, https://[2a0a:e5c0:10:1:225:b3ff:fe20:375c]:2379, false
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371b8a07185dee7e, started, server63, https://[2a0a:e5c0:10:1:225:b3ff:fe20:378a]:2380, https://[2a0a:e5c0:10:1:225:b3ff:fe20:378a]:2379, false
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5942bc58307f8af9, started, server83, https://[2a0a:e5c0:10:1:3e4a:92ff:fe79:bb98]:2380, https://[2a0a:e5c0:10:1:3e4a:92ff:fe79:bb98]:2379, false
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[10:48] line:~% kubectl exec -n kube-system -ti etcd-server65 -- etcdctl --endpoints '[::1]:2379' --cacert /etc/kubernetes/pki/etcd/ca.crt --cert  /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.key member remove 371b8a07185dee7e
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Member 371b8a07185dee7e removed from cluster e3c0805f592a8f77
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</pre>
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SEE ALSO
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* We found the solution using https://stackoverflow.com/questions/67921552/re-installed-node-cannot-join-kubernetes-cluster
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h3. Hardware Maintenance using ungleich-hardware
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Use the following manifest and replace the HOST with the actual host:
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<pre>
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apiVersion: v1
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kind: Pod
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metadata:
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  name: ungleich-hardware-HOST
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spec:
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  containers:
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  - name: ungleich-hardware
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    image: ungleich/ungleich-hardware:0.0.5
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    args:
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    - sleep
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    - "1000000"
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    volumeMounts:
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      - mountPath: /dev
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        name: dev
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    securityContext:
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      privileged: true
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  nodeSelector:
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    kubernetes.io/hostname: "HOST"
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  volumes:
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    - name: dev
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      hostPath:
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        path: /dev
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</pre>
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Also see: [[The_ungleich_hardware_maintenance_guide]]
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h3. Triggering a cronjob / creating a job from a cronjob
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To test a cronjob, we can create a job from a cronjob:
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<pre>
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kubectl create job --from=cronjob/volume2-daily-backup volume2-manual
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</pre>
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This creates a job volume2-manual based on the cronjob  volume2-daily
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h3. su-ing into a user that has nologin shell set
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Many times users are having nologin as their shell inside the container. To be able to execute maintenance commands within the
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container, we can use @su -s /bin/sh@ like this:
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<pre>
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su -s /bin/sh -c '/path/to/your/script' testuser
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</pre>
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Found on https://serverfault.com/questions/351046/how-to-run-command-as-user-who-has-usr-sbin-nologin-as-shell
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h3. How to print a secret value
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Assuming you want the "password" item from a secret, use:
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<pre>
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kubectl get secret SECRETNAME -o jsonpath="{.data.password}" | base64 -d; echo "" 
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</pre>
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h2. Calico CNI
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h3. Calico Installation
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* We install "calico using helm":https://docs.projectcalico.org/getting-started/kubernetes/helm
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* This has the following advantages:
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** Easy to upgrade
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** Does not require os to configure IPv6/dual stack settings as the tigera operator figures out things on its own
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Usually plain calico can be installed directly using:
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<pre>
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helm repo add projectcalico https://docs.projectcalico.org/charts
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helm upgrade --install --namespace tigera calico projectcalico/tigera-operator --version v3.23.2 --create-namespace
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# helm install --namespace tigera calico projectcalico/tigera-operator --version v3.23.2 --create-namespace
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</pre>
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* Check the tags on https://github.com/projectcalico/calico/tags for the latest release
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h3. Installing calicoctl
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* General installation instructions, including binary download: https://projectcalico.docs.tigera.io/maintenance/clis/calicoctl/install
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To be able to manage and configure calico, we need to 
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"install calicoctl (we choose the version as a pod)":https://docs.projectcalico.org/getting-started/clis/calicoctl/install#install-calicoctl-as-a-kubernetes-pod
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<pre>
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kubectl apply -f https://docs.projectcalico.org/manifests/calicoctl.yaml
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</pre>
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Or version specific:
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<pre>
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kubectl apply -f https://github.com/projectcalico/calico/blob/v3.20.4/manifests/calicoctl.yaml
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# For 3.22
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kubectl apply -f https://projectcalico.docs.tigera.io/archive/v3.22/manifests/calicoctl.yaml
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</pre>
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And making it easier accessible by alias:
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<pre>
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alias calicoctl="kubectl exec -i -n kube-system calicoctl -- /calicoctl"
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</pre>
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h3. Calico configuration
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By default our k8s clusters "BGP peer":https://docs.projectcalico.org/networking/bgp
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with an upstream router to propagate podcidr and servicecidr.
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Default settings in our infrastructure:
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* We use a full-mesh using the @nodeToNodeMeshEnabled: true@ option
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* We keep the original next hop so that *only* the server with the pod is announcing it (instead of ecmp)
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* We use private ASNs for k8s clusters
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* We do *not* use any overlay
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After installing calico and calicoctl the last step of the installation is usually:
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<pre>
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calicoctl create -f - < calico-bgp.yaml
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</pre>
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A sample BGP configuration:
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<pre>
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---
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apiVersion: projectcalico.org/v3
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kind: BGPConfiguration
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metadata:
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  name: default
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spec:
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  logSeverityScreen: Info
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  nodeToNodeMeshEnabled: true
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  asNumber: 65534
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  serviceClusterIPs:
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  - cidr: 2a0a:e5c0:10:3::/108
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  serviceExternalIPs:
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  - cidr: 2a0a:e5c0:10:3::/108
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---
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apiVersion: projectcalico.org/v3
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kind: BGPPeer
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metadata:
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  name: router1-place10
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spec:
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  peerIP: 2a0a:e5c0:10:1::50
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  asNumber: 213081
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  keepOriginalNextHop: true
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</pre>
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h2. ArgoCD 
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h3. Argocd Installation
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* See https://argo-cd.readthedocs.io/en/stable/
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As there is no configuration management present yet, argocd is installed using
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<pre>
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kubectl create namespace argocd
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# Specific Version
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kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/v2.3.2/manifests/install.yaml
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# OR: latest stable
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kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
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</pre>
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h3. Get the argocd credentials
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kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d; echo ""
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</pre>
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h3. Accessing argocd
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In regular IPv6 clusters:
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* Navigate to https://argocd-server.argocd.CLUSTERDOMAIN
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In legacy IPv4 clusters
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<pre>
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kubectl --namespace argocd port-forward svc/argocd-server 8080:80
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</pre>
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* Navigate to https://localhost:8080
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h3. Using the argocd webhook to trigger changes
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* To trigger changes post json https://argocd.example.com/api/webhook
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h3. Deploying an application
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* Applications are deployed via git towards gitea (code.ungleich.ch) and then pulled by argo
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* Always include the *redmine-url* pointing to the (customer) ticket
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** Also add the support-url if it exists
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Application sample
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apiVersion: argoproj.io/v1alpha1
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kind: Application
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metadata:
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  name: gitea-CUSTOMER
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  namespace: argocd
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spec:
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  destination:
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    namespace: default
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    server: 'https://kubernetes.default.svc'
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  source:
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    path: apps/prod/gitea
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    repoURL: 'https://code.ungleich.ch/ungleich-intern/k8s-config.git'
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    targetRevision: HEAD
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    helm:
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      parameters:
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        - name: storage.data.storageClass
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          value: rook-ceph-block-hdd
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        - name: storage.data.size
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          value: 200Gi
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        - name: storage.db.storageClass
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          value: rook-ceph-block-ssd
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        - name: storage.db.size
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          value: 10Gi
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        - name: storage.letsencrypt.storageClass
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          value: rook-ceph-block-hdd
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        - name: storage.letsencrypt.size
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          value: 50Mi
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        - name: letsencryptStaging
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          value: 'no'
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        - name: fqdn
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          value: 'code.verua.online'
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  project: default
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  syncPolicy:
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    automated:
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      prune: true
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      selfHeal: true
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  info:
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    - name: 'redmine-url'
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      value: 'https://redmine.ungleich.ch/issues/ISSUEID'
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    - name: 'support-url'
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      value: 'https://support.ungleich.ch/Ticket/Display.html?id=TICKETID'
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</pre>
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h2. Helm related operations and conventions
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We use helm charts extensively.
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* In production, they are managed via argocd
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* In development, helm chart can de developed and deployed manually using the helm utility.
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h3. Installing a helm chart
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One can use the usual pattern of
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<pre>
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helm install <releasename> <chartdirectory>
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</pre>
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However often you want to reinstall/update when testing helm charts. The following pattern is "better", because it allows you to reinstall, if it is already installed:
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<pre>
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helm upgrade --install <releasename> <chartdirectory>
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</pre>
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h3. Naming services and deployments in helm charts [Application labels]
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* We always have {{ .Release.Name }} to identify the current "instance"
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* Deployments:
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** use @app: <what it is>@, f.i. @app: nginx@, @app: postgres@, ...
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* See more about standard labels on
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** https://kubernetes.io/docs/concepts/overview/working-with-objects/common-labels/
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** https://helm.sh/docs/chart_best_practices/labels/
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h2. Rook / Ceph Related Operations
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h3. Executing ceph commands
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Using the ceph-tools pod as follows:
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<pre>
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kubectl exec -n rook-ceph -ti $(kubectl -n rook-ceph get pods -l app=rook-ceph-tools -o jsonpath='{.items[*].metadata.name}') -- ceph -s
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</pre>
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h3. Inspecting the logs of a specific server
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<pre>
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# Get the related pods
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kubectl -n rook-ceph get pods -l app=rook-ceph-osd-prepare 
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...
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# Inspect the logs of a specific pod
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kubectl -n rook-ceph logs -f rook-ceph-osd-prepare-server23--1-444qx
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</pre>
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h3. Inspecting the logs of the rook-ceph-operator
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<pre>
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kubectl -n rook-ceph logs -f -l app=rook-ceph-operator
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</pre>
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h3. Restarting the rook operator
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<pre>
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kubectl -n rook-ceph delete pods  -l app=rook-ceph-operator
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</pre>
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h3. Triggering server prepare / adding new osds
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The rook-ceph-operator triggers/watches/creates pods to maintain hosts. To trigger a full "re scan", simply delete that pod:
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<pre>
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kubectl -n rook-ceph delete pods -l app=rook-ceph-operator
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</pre>
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This will cause all the @rook-ceph-osd-prepare-..@ jobs to be recreated and thus OSDs to be created, if new disks have been added.
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h3. Removing an OSD
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* See "Ceph OSD Management":https://rook.io/docs/rook/v1.7/ceph-osd-mgmt.html
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* More specifically: https://github.com/rook/rook/blob/release-1.7/cluster/examples/kubernetes/ceph/osd-purge.yaml
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* Then delete the related deployment
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Set osd id in the osd-purge.yaml and apply it. OSD should be down before.
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<pre>
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apiVersion: batch/v1
580
kind: Job
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metadata:
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  name: rook-ceph-purge-osd
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  namespace: rook-ceph # namespace:cluster
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  labels:
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    app: rook-ceph-purge-osd
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spec:
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  template:
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    metadata:
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      labels:
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        app: rook-ceph-purge-osd
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    spec:
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      serviceAccountName: rook-ceph-purge-osd
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      containers:
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        - name: osd-removal
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          image: rook/ceph:master
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          # TODO: Insert the OSD ID in the last parameter that is to be removed
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          # The OSD IDs are a comma-separated list. For example: "0" or "0,2".
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          # If you want to preserve the OSD PVCs, set `--preserve-pvc true`.
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          #
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          # A --force-osd-removal option is available if the OSD should be destroyed even though the
601
          # removal could lead to data loss.
602
          args:
603
            - "ceph"
604
            - "osd"
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            - "remove"
606
            - "--preserve-pvc"
607
            - "false"
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            - "--force-osd-removal"
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            - "false"
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            - "--osd-ids"
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            - "SETTHEOSDIDHERE"
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          env:
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            - name: POD_NAMESPACE
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              valueFrom:
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                fieldRef:
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                  fieldPath: metadata.namespace
617
            - name: ROOK_MON_ENDPOINTS
618
              valueFrom:
619
                configMapKeyRef:
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                  key: data
621
                  name: rook-ceph-mon-endpoints
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            - name: ROOK_CEPH_USERNAME
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              valueFrom:
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                secretKeyRef:
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                  key: ceph-username
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                  name: rook-ceph-mon
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            - name: ROOK_CEPH_SECRET
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              valueFrom:
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                secretKeyRef:
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                  key: ceph-secret
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                  name: rook-ceph-mon
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            - name: ROOK_CONFIG_DIR
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              value: /var/lib/rook
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            - name: ROOK_CEPH_CONFIG_OVERRIDE
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              value: /etc/rook/config/override.conf
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            - name: ROOK_FSID
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              valueFrom:
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                secretKeyRef:
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                  key: fsid
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                  name: rook-ceph-mon
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            - name: ROOK_LOG_LEVEL
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              value: DEBUG
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          volumeMounts:
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            - mountPath: /etc/ceph
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              name: ceph-conf-emptydir
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            - mountPath: /var/lib/rook
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              name: rook-config
648
      volumes:
649
        - emptyDir: {}
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          name: ceph-conf-emptydir
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        - emptyDir: {}
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          name: rook-config
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      restartPolicy: Never
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</pre>
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Deleting the deployment:
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<pre>
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[18:05] bridge:~% kubectl -n rook-ceph delete deployment rook-ceph-osd-6
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deployment.apps "rook-ceph-osd-6" deleted
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</pre>
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h2. Harbor
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* We user "Harbor":https://goharbor.io/ for caching and as an image registry. Internal app reference: apps/prod/harbor.
668
* The admin password is in the password store, auto generated per cluster
669
* At the moment harbor only authenticates against the internal ldap tree
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h3. LDAP configuration
672
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* The url needs to be ldaps://...
674
* uid = uid
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* rest standard
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h2. Monitoring / Prometheus
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* Via "kube-prometheus":https://github.com/prometheus-operator/kube-prometheus/
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Access via ...
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683
* http://prometheus-k8s.monitoring.svc:9090
684
* http://grafana.monitoring.svc:3000
685
* http://alertmanager.monitoring.svc:9093
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h3. Prometheus Options
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690
* "helm/kube-prometheus-stack":https://github.com/prometheus-community/helm-charts/tree/main/charts/kube-prometheus-stack
691
** Includes dashboards and co.
692
* "manifest based kube-prometheus":https://github.com/prometheus-operator/kube-prometheus
693
** Includes dashboards and co.
694
* "Prometheus Operator (mainly CRD manifest":https://github.com/prometheus-operator/prometheus-operator
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h2. Nextcloud
698
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h3. How to get the nextcloud credentials 
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701
* The initial username is set to "nextcloud"
702
* The password is autogenerated and saved in a kubernetes secret
703
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<pre>
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kubectl get secret RELEASENAME-nextcloud -o jsonpath="{.data.PASSWORD}" | base64 -d; echo "" 
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</pre>
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h3. How to fix "Access through untrusted domain"
709
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* Nextcloud stores the initial domain configuration
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* If the FQDN is changed, it will show the error message "Access through untrusted domain"
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* To fix, edit /var/www/html/config/config.php and correct the domain
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* Then delete the pods
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h2. Infrastructure versions
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h3. ungleich kubernetes infrastructure v5 (2021-10)
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Clusters are configured / setup in this order:
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* Bootstrap via kubeadm
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* "Networking via calico + BGP (non ECMP) using helm":https://docs.projectcalico.org/getting-started/kubernetes/helm
723
* "ArgoCD for CD":https://argo-cd.readthedocs.io/en/stable/
724
** "rook for storage via argocd":https://rook.io/
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** haproxy for in IPv6-cluster-IPv4-to-IPv6 proxy via argocd
726
** "kubernetes-secret-generator for in cluster secrets":https://github.com/mittwald/kubernetes-secret-generator
727
** "ungleich-certbot managing certs and nginx":https://hub.docker.com/repository/docker/ungleich/ungleich-certbot
728
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730
h3. ungleich kubernetes infrastructure v4 (2021-09)
731
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* rook is configured via manifests instead of using the rook-ceph-cluster helm chart
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* The rook operator is still being installed via helm
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h3. ungleich kubernetes infrastructure v3 (2021-07)
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* rook is now installed via helm via argocd instead of directly via manifests
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h3. ungleich kubernetes infrastructure v2 (2021-05)
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741
* Replaced fluxv2 from ungleich k8s v1 with argocd
742 1 Nico Schottelius
** argocd can apply helm templates directly without needing to go through Chart releases
743 28 Nico Schottelius
* We are also using argoflow for build flows
744
* Planned to add "kaniko":https://github.com/GoogleContainerTools/kaniko for image building
745
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h3. ungleich kubernetes infrastructure v1 (2021-01)
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748
We are using the following components:
749
750
* "Calico as a CNI":https://www.projectcalico.org/ with BGP, IPv6 only, no encapsulation
751
** Needed for basic networking
752
* "kubernetes-secret-generator":https://github.com/mittwald/kubernetes-secret-generator for creating secrets
753
** Needed so that secrets are not stored in the git repository, but only in the cluster
754
* "ungleich-certbot":https://hub.docker.com/repository/docker/ungleich/ungleich-certbot
755
** Needed to get letsencrypt certificates for services
756
* "rook with ceph rbd + cephfs":https://rook.io/ for storage
757
** rbd for almost everything, *ReadWriteOnce*
758
** cephfs for smaller things, multi access *ReadWriteMany*
759
** Needed for providing persistent storage
760
* "flux v2":https://fluxcd.io/
761
** Needed to manage resources automatically