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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**.