The ungleich monitoring infrastructure » History » Revision 16
Revision 15 (Nico Schottelius, 07/07/2020 07:42 AM) → Revision 16/35 (Nico Schottelius, 07/07/2020 09:55 AM)
h1. The ungleich monitoring infrastructure
{{>toc}}
h2. Introduction
We use the following technology / products for the monitoring:
* consul (service discovery)
* prometheus (exporting, gathering, alerting)
* Grafana (presenting)
Prometheus and grafana are located on the monitoring control machines
* monitoring.place5.ungleich.ch
* monitoring.place6.ungleich.ch
h2. Consul
We use a consul cluster for each datacenter (e.g. place5 and place6).
The servers are located on the physical machines (red{1..3} resp. black{1..3}) and the agents are running on all other monitored machines (such as servers and VMs)
consul is configured to publish the service its host is providing (e.g. the exporters)
There is a inter-datacenter communication (wan gossip) [https://www.consul.io/docs/guides/datacenters.html]
h2. Prometheus
Prometheus is responsible to get all data out (exporters) of the monitored host and store them. Also to send out alerts if needed (alertmanager)
h3. Exporters
* Node (host specific metrics (e.g. CPU-, RAM-, Disk-usage..))
* Ceph (Ceph specific metrics (e.g. pool usage, osds ..))
* blackbox (Metrics about online state of http/https services)
The node exporter is located on all monitored hosts
Ceph exporter is porvided by ceph itself and is located on the ceph manager.
The blackbox exporter is located on the monitoring control machine itself.
h3. Alerts
We configured the following alerts:
* ceph osds down
* ceph health state is not OK
* ceph quorum not OK
* ceph pool disk usage too high
* ceph disk usage too high
* instance down
* disk usage too high
* Monitored website down
h2. Grafana
Grafana provides dashboards for the following:
* Node (metrics about CPU-, RAM-, Disk and so on usage)
* blackbox (metrics about the blackbox exporter)
* ceph (important metrics from the ceph exporter)
h3. Authentication
The grafana authentication works over ldap. (See [[The ungleich LDAP guide]])
All users in the @devops@ group will be mapped to the Admin role, all other users will be Viewers
h2. Monit
We use "monit":https://mmonit.com/ for monitoring and restarting daemons. See `__ungleich_monit` type in dot-cdist.
h2. Misc
* You're probably looking for the `__dcl_monitoring_server` type, which centralize a bunch of stuff.
* This page needs some love!
h2. Service/Customer monitoring
* A few blackbox things can be found on the datacenter monitoring infrastructure.
* There's a new prometheus+grafana setup at https://service-monitoring.ungleich.ch/, deployed by @fnux for Matrix-as-a-Service monitoring. At time of writing, it also monitors the VPN server and staticwebhosting. No alertmanager yet. Partially manual.
h2. Monitoring Guide
h3. Configuring prometheus
Use @promtool check config@ to verify the configuration.
<pre>
[21:02:48] server1.place11:~# promtool check config /etc/prometheus/prometheus.yml
Checking /etc/prometheus/prometheus.yml
SUCCESS: 4 rule files found
Checking /etc/prometheus/blackbox.rules
SUCCESS: 3 rules found
Checking /etc/prometheus/ceph-alerts.rules
SUCCESS: 8 rules found
Checking /etc/prometheus/node-alerts.rules
SUCCESS: 8 rules found
Checking /etc/prometheus/uplink-monitoring.rules
SUCCESS: 1 rules found
</pre>
h3. Querying prometheus
Use @promtool query instant@ to query values:
<pre>
[21:00:26] server1.place11:~# promtool query instant http://localhost:9090 'probe_success{dc="place5"} == 1'
probe_success{dc="place5", instance="193.192.225.73", job="routers-place5", protocol="ipv4", sensiblehostname="router1"} => 1 @[1593889492.577]
probe_success{dc="place5", instance="195.141.230.103", job="routers-place5", protocol="ipv4", sensiblehostname="router2"} => 1 @[1593889492.577]
probe_success{dc="place5", instance="2001:1700:3500::12", job="routers-place5", protocol="ipv6", sensiblehostname="router2"} => 1 @[1593889492.577]
probe_success{dc="place5", instance="2001:1700:3500::2", job="routers-place5", protocol="ipv6", sensiblehostname="router1"} => 1 @[1593889492.577]
</pre>
Typical queries:
Creating a sum of all metrics that contains a common label. For instance summing over all jobs:
<pre>
sum by (job) (probe_success)
[17:07:58] server1.place11:/etc/prometheus# promtool query instant http://localhost:9090 'sum by (job) (probe_success)
'
{job="routers-place5"} => 4 @[1593961699.969]
{job="uplink-place5"} => 4 @[1593961699.969]
{job="routers-place6'"} => 4 @[1593961699.969]
{job="uplink-place6"} => 4 @[1593961699.969]
{job="core-services"} => 3 @[1593961699.969]
[17:08:19] server1.place11:/etc/prometheus#
</pre>
Combining different metrics for filtering. For instance to filter all metrics of type "probe_success" which also have a metric probe_ip_protocol with value = 4
* probe_ip_protocol{dc="place5", instance="147.78.195.249", job="routers-place5", protocol="ipv4"} => 4 @[1593961766.619]
The operator @on@ is used to filter
<pre>
sum(probe_success * on(instance) probe_ip_protocol == 4)
</pre>
Creating an alert:
* if the sum of all jobs of a certain regex and match on ip protocol is 0
** this particular job indicates total loss of connectivity
* We want to get a vector like this:
** job="routers-place5", protocol = 4
** job="uplink-place5", protocol = 4
** job="routers-place5", protocol = 6
** job="uplink-place5", protocol = 6
Query for IPv4 of all routers:
<pre>
[17:09:26] server1.place11:/etc/prometheus# promtool query instant http://localhost:9090 'sum(probe_success{job=~"routers-.*"} * on(instance) group_left(job) probe_ip_protocol == 4) by (job)'
{job="routers-place5"} => 8 @[1593963562.281]
{job="routers-place6'"} => 8 @[1593963562.281]
</pre>
Query for all IPv4 of all routers:
<pre>
[17:39:22] server1.place11:/etc/prometheus# promtool query instant http://localhost:9090 'sum(probe_success{job=~"routers-.*"} * on(instance) group_left(job) probe_ip_protocol == 6) by (job)'
{job="routers-place5"} => 12 @[1593963626.483]
{job="routers-place6'"} => 12 @[1593963626.483]
[17:40:26] server1.place11:/etc/prometheus#
</pre>
Query for all IPv6 uplinks:
<pre>
[17:40:26] server1.place11:/etc/prometheus# promtool query instant http://localhost:9090 'sum(probe_success{job=~"uplink-.*"} * on(instance) group_left(job) probe_ip_protocol == 6) by (job)'
{job="uplink-place5"} => 12 @[1593963675.835]
{job="uplink-place6"} => 12 @[1593963675.835]
[17:41:15] server1.place11:/etc/prometheus#
</pre>
Query for all IPv4 uplinks:
<pre>
[17:41:15] server1.place11:/etc/prometheus# promtool query instant http://localhost:9090 'sum(probe_success{job=~"uplink-.*"} * on(instance) group_left(job) probe_ip_protocol == 4) by (job)'
{job="uplink-place5"} => 8 @[1593963698.108]
{job="uplink-place6"} => 8 @[1593963698.108]
</pre>
The values 8 and 12 means:
* 8 = 4 (ip version 4) * probe_success (2 routers are up)
* 8 = 6 (ip version 6) * probe_success (2 routers are up)
To normalise, we would need to divide by 4 (or 6):
<pre>
[17:41:38] server1.place11:/etc/prometheus# promtool query instant http://localhost:9090 'sum(probe_success{job=~"uplink-.*"} * on(instance) group_left(job) probe_ip_protocol == 4) by (job) / 4'
{job="uplink-place5"} => 2 @[1593963778.885]
{job="uplink-place6"} => 2 @[1593963778.885]
[17:42:58] server1.place11:/etc/prometheus# promtool query instant http://localhost:9090 'sum(probe_success{job=~"uplink-.*"} * on(instance) group_left(job) probe_ip_protocol == 6) by (job) / 6'
{job="uplink-place5"} => 2 @[1593963788.276]
{job="uplink-place6"} => 2 @[1593963788.276]
</pre>
However if we are only interested in whether 0 are up, it does not matter as 0*4 = 0 and 0*6 = 0.
h3. Using Grafana
* Username for changing items: "admin"
* Username for viewing dashboards: "ungleich"
* Passwords in the password store
h3. Managing alerts
* Read https://prometheus.io/docs/practices/alerting/ as an introduction
* Use @amtool@
Showing current alerts:
<pre>
[14:54:35] monitoring.place6:~# amtool alert query
Alertname Starts At Summary
InstanceDown 2020-07-01 10:24:03 CEST Instance red1.place5.ungleich.ch down
InstanceDown 2020-07-01 10:24:03 CEST Instance red3.place5.ungleich.ch down
InstanceDown 2020-07-05 12:51:03 CEST Instance apu-router2.place5.ungleich.ch down
UngleichServiceDown 2020-07-05 13:51:19 CEST Ungleich internal service https://staging.swiss-crowdfunder.com down
InstanceDown 2020-07-05 13:55:33 CEST Instance https://swiss-crowdfunder.com down
CephHealthSate 2020-07-05 13:59:49 CEST Ceph Cluster is not healthy.
LinthalHigh 2020-07-05 14:01:41 CEST Temperature on risinghf-19 is 32.10012512207032
[14:54:41] monitoring.place6:~#
</pre>
Silencing alerts:
<pre>
[14:59:45] monitoring.place6:~# amtool silence add -c "Ceph is actually fine" alertname=CephHealthSate
4a5c65ff-4af3-4dc9-a6e0-5754b00cd2fa
[15:00:06] monitoring.place6:~# amtool silence query
ID Matchers Ends At Created By Comment
4a5c65ff-4af3-4dc9-a6e0-5754b00cd2fa alertname=CephHealthSate 2020-07-05 14:00:06 UTC root Ceph is actually fine
[15:00:13] monitoring.place6:~#
</pre>
Better using author and co. TOBEFIXED
h3. Severity levels
The following notions are used:
* critical = panic = calling to the whole team
* warning = something needs to be fixed = email to sre, non paging
* info = not good, might be an indication for fixing something, goes to a matrix room
h3. Labeling
Labeling in Prometheus is a science on its own and has a lot of pitfalls. Let's start with some:
* The @relabel_configs@ are applied BEFORE scraping
* The @metric_relabel_configs@ are applied AFTER scraping (contains different labels!)
* regular expression are not the "default" RE, but "RE2":https://github.com/google/re2/wiki/Syntax
* metric_label_config does not apply to automatic labels like @up@ !
** You need to use relabel_configs
h3. Setting "roles"
We use the label "role" to define a primary purpose per host. Example from 2020-07-07:
<pre>
relabel_configs:
- source_labels: [__address__]
regex: '.*(server|monitor|canary-vm|vpn|server|apu-router|router).*.ungleich.ch.*'
target_label: 'role'
replacement: '$1'
- source_labels: [__address__]
regex: 'ciara.*.ungleich.ch.*'
target_label: 'role'
replacement: 'server'
- source_labels: [__address__]
regex: '.*:9283'
target_label: 'role'
replacement: 'ceph'
- source_labels: [__address__]
regex: '((ciara2|ciara4).*)'
target_label: 'role'
replacement: 'down'
- source_labels: [__address__]
regex: '.*(place.*).ungleich.ch.*'
target_label: 'dc'
replacement: '$1'
</pre>
What happens here:
* __address__ contains the hostname+port, f.i. server1.placeX.ungleich.ch:9100
* We apply some roles by default (the server, monitor etc.)
* Special rule for ciara, which does not match the serverX pattern
* ciara2 and ciara4 in above example are intentionally down
* At the end we setup the "dc" label in case the host is in a place of ungleich
h3. Marking hosts down
If a host or service is intentionally down, **change its role** to **down**.