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The ungleich kubernetes infrastructure » History » Revision 33

Revision 32 (Nico Schottelius, 08/20/2021 09:18 AM) → Revision 33/213 (Nico Schottelius, 08/20/2021 09:18 AM)

h1. The ungleich kubernetes infrastructure and ungleich kubernetes manual 

 {{toc}} 

 h2. Status 

 This document is **pre-production**. 
 This document is to become the ungleich kubernetes infrastructure overview as well as the ungleich kubernetes manual. 

 h2. k8s clusters 

 | Cluster       | Purpose         | Master(s) | 
 | c0.k8s.ooo    | Dev             | | 
 | c1.k8s.ooo    | Dev p6          | 2a0a-e5c0-2-11-0-62ff-fe0b-1a3d.k8s-1.place6.ungleich.ch | 
 | c2.k8s.ooo    | Demo place7     | server47 server53 server54 |  
 | c3.k8s.ooo    | Test p7         | Raspberry PIs (inactive of 2021-08-20) | 
 | c4.k8s.ooo    | active-dev p7 | server52 server53 server54 | 
 | c5.k8s.ooo    | Development Amal | 2a0a-e5c0-2-11-0-62ff-fe0b-1a46.k8s-1.place6.ungleich.ch | 
 | p6.k8s.ooo    | planned         | | 
 | p10.k8s.ooo | production      | | 

 h2. General architecture and components overview 

 * All k8s clusters are IPv6 only 
 * We use BGP peering to propagate podcidr and serviceCidr networks to our infrastructure 
 * The main public testing repository is "ungleich-k8s":https://code.ungleich.ch/ungleich-public/ungleich-k8s 
 ** Private configurations are found in the **k8s-config** repository 

 h3. Cluster types 

 | **Type/Feature**              | **Development**                  | **Production**           | 
 | Min No. nodes                 | 3 (1 master, 3 worker)           | 5 (3 master, 3 worker) | 
 | Recommended minimum           | 4 (dedicated master, 3 worker) | 8 (3 master, 5 worker) | 
 | Separation of control plane | optional                         | recommended              | 
 | Persistent storage            | required                         | required                 | 
 | Number of storage monitors    | 3                                | 5                        | 

 h2. Operations 

 h3. Installing a new k8s cluster 

 * Decide on the cluster name (usually *cX.k8s.ooo*), X counting upwards 
 ** Using pXX.k8s.ooo for production clusters of placeXX 
 * Use cdist to configure the nodes with requirements like crio 
 * Decide between single or multi node control plane setups (see below) 
 ** Single control plane suitable for development clusters 

 Typical init procedure: 

 * Single control plane: @kubeadm init --config bootstrap/XXX/kubeadm.yaml@ 
 * Multi control plane (HA): @kubeadm init --config bootstrap/XXX/kubeadm.yaml --upload-certs@ 

 h3. Deleting a pod that is hanging in terminating state 

 <pre> 
 kubectl delete pod <PODNAME> --grace-period=0 --force --namespace <NAMESPACE> 
 </pre> 

 (from https://stackoverflow.com/questions/35453792/pods-stuck-in-terminating-status) 


 h2. Infrastructure versions 

 h3. ungleich kubernetes infrastructure v2 

 * Replaced fluxv2 from ungleich k8s v1 with argocd 
 ** argocd can apply helm templates directly without needing to go through Chart releases 
 * We are also using argoflow for build flows 
 * Planned to add "kaniko":https://github.com/GoogleContainerTools/kaniko for image building 

 h3. ungleich kubernetes infrastructure v1 

 We are using the following components: 

 * "Calico as a CNI":https://www.projectcalico.org/ with BGP, IPv6 only, no encapsulation 
 ** Needed for basic networking 
 * "kubernetes-secret-generator":https://github.com/mittwald/kubernetes-secret-generator for creating secrets 
 ** Needed so that secrets are not stored in the git repository, but only in the cluster 
 * "ungleich-certbot":https://hub.docker.com/repository/docker/ungleich/ungleich-certbot 
 ** Needed to get letsencrypt certificates for services 
 * "rook with ceph rbd + cephfs":https://rook.io/ for storage 
 ** rbd for almost everything, *ReadWriteOnce* 
 ** cephfs for smaller things, multi access *ReadWriteMany* 
 ** Needed for providing persistent storage 
 * "flux v2":https://fluxcd.io/ 
 ** Needed to manage resources automatically