Kubernetes : Deploy Prometheus2022/11/03

Deploy Prometheus to monitor metrics in Kubernetes Cluster.

This example is based on the environment like follows.

-----------+---------------------------+--------------------------+------------
           |                           |                          |
       eth0|10.0.0.25              eth0|10.0.0.71             eth0|10.0.0.72
+----------+-----------+   +-----------+-----------+   +-----------+-----------+
|  [ ctrl.srv.world ]  |   |  [snode01.srv.world]  |   |  [snode02.srv.world]  |
|     Control Plane    |   |      Worker Node      |   |      Worker Node      |
+----------------------+   +-----------------------+   +-----------------------+

[1]	A Persistent storage is needed for Prometheus. On this example, install NFS Server on Control Plane Node and configure [/home/nfsshare] directory as NFS share as external persistent storage, and also configure dynamic volume provisioning with NFS plugin like the example of [1], [2], [3].
[2]	Install Prometheus chart with Helm.

# output config and change some settings

root@ctrl:~#

helm inspect values bitnami/kube-prometheus > prometheus.yaml

root@ctrl:~#

vi prometheus.yaml

.....
.....
    line 18 : specify [storageClass] to use
    storageClass: "nfs-client"
.....
.....
.....
    line 995 : specify [storageClass] to use
    storageClass: "nfs-client"
.....
.....
.....
    line 1840 : specify [storageClass] to use
    storageClass: "nfs-client"

# create a namespace for Prometheus

root@ctrl:~#

kubectl create namespace monitoring

namespace/monitoring created

root@ctrl:~#

helm install prometheus --namespace monitoring -f prometheus.yaml bitnami/kube-prometheus

NAME: prometheus
LAST DEPLOYED: Thu Nov  3 07:23:48 2022
NAMESPACE: monitoring
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
CHART NAME: kube-prometheus
CHART VERSION: 8.1.11
APP VERSION: 0.60.1

** Please be patient while the chart is being deployed **

Watch the Prometheus Operator Deployment status using the command:

    kubectl get deploy -w --namespace monitoring -l app.kubernetes.io/name=kube-prometheus-operator,app.kubernetes.io/instance=prometheus

Watch the Prometheus StatefulSet status using the command:

    kubectl get sts -w --namespace monitoring -l app.kubernetes.io/name=kube-prometheus-prometheus,app.kubernetes.io/instance=prometheus

Prometheus can be accessed via port "9090" on the following DNS name from within your cluster:

    prometheus-kube-prometheus-prometheus.monitoring.svc.cluster.local

To access Prometheus from outside the cluster execute the following commands:

    echo "Prometheus URL: http://127.0.0.1:9090/"
    kubectl port-forward --namespace monitoring svc/prometheus-kube-prometheus-prometheus 9090:9090

Watch the Alertmanager StatefulSet status using the command:

    kubectl get sts -w --namespace monitoring -l app.kubernetes.io/name=kube-prometheus-alertmanager,app.kubernetes.io/instance=prometheus

Alertmanager can be accessed via port "9093" on the following DNS name from within your cluster:

    prometheus-kube-prometheus-alertmanager.monitoring.svc.cluster.local

To access Alertmanager from outside the cluster execute the following commands:

    echo "Alertmanager URL: http://127.0.0.1:9093/"
    kubectl port-forward --namespace monitoring svc/prometheus-kube-prometheus-alertmanager 9093:9093

root@ctrl:~#

kubectl get pods -n monitoring -o wide

NAME                                                           READY   STATUS    RESTARTS      AGE     IP                NODE                NOMINATED NODE   READINESS GATES
alertmanager-prometheus-kube-prometheus-alertmanager-0         2/2     Running   1 (96s ago)   106s    192.168.211.131   snode02.srv.world   <none>           <none>
prometheus-kube-prometheus-blackbox-exporter-ff46dc456-ft2z2   1/1     Running   0             2m11s   192.168.211.130   snode02.srv.world   <none>           <none>
prometheus-kube-prometheus-operator-6b75d4f48b-vf95h           1/1     Running   0             2m11s   192.168.186.67    snode01.srv.world   <none>           <none>
prometheus-kube-state-metrics-85647b4c64-r58qp                 1/1     Running   0             2m11s   192.168.186.68    snode01.srv.world   <none>           <none>
prometheus-node-exporter-lmww4                                 1/1     Running   0             2m11s   10.0.0.72         snode02.srv.world   <none>           <none>
prometheus-node-exporter-zt5dp                                 1/1     Running   0             2m11s   10.0.0.71         snode01.srv.world   <none>           <none>
prometheus-prometheus-kube-prometheus-prometheus-0             2/2     Running   0             106s    192.168.186.69    snode01.srv.world   <none>           <none>

# if access from outside of cluster, set port-forwarding

root@ctrl:~#

kubectl port-forward -n monitoring service/prometheus-kube-prometheus-prometheus --address 0.0.0.0 9090:9090

[3]	If you deploy Grafana, too, It's possible like follows.

# output config and change some settings

root@ctrl:~#

helm inspect values bitnami/grafana > grafana.yaml

root@ctrl:~#

vi grafana.yaml

# line 552 : change to your [storageClass]
persistence:
  enabled: true
  ## If defined, storageClassName: <storageClass>
  ## If set to "-", storageClassName: "", which disables dynamic provisioning
  ## If undefined (the default) or set to null, no storageClassName spec is
  ##   set, choosing the default provisioner.  (gp2 on AWS, standard on
  ##   GKE, AWS & OpenStack)
  ##
  storageClass: "nfs-client"

root@ctrl:~#

helm install grafana --namespace monitoring -f grafana.yaml bitnami/grafana

NAME: grafana
LAST DEPLOYED: Thu Nov  3 07:40:10 2022
NAMESPACE: monitoring
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
CHART NAME: grafana
CHART VERSION: 8.2.15
APP VERSION: 9.2.3

** Please be patient while the chart is being deployed **

1. Get the application URL by running these commands:
    echo "Browse to http://127.0.0.1:8080"
    kubectl port-forward svc/grafana 8080:3000 &

2. Get the admin credentials:

    echo "User: admin"
    echo "Password: $(kubectl get secret grafana-admin --namespace monitoring -o jsonpath="{.data.GF_SECURITY_ADMIN_PASSWORD}" | base64 -d)"

root@ctrl:~#

kubectl get pods -n monitoring

NAME                                                           READY   STATUS    RESTARTS      AGE
grafana-57dc4598d9-zhwvg                                       1/1     Running   0             68s
.....
.....

# if access from outside of cluster, set port-forwarding

root@ctrl:~#

kubectl port-forward -n monitoring service/grafana --address 0.0.0.0 3000:3000

[4]

If you access to Prometheus UI from a Host in cluster, access to the URL below with an Web browser.

⇒ http://prometheus-kube-prometheus-prometheus.monitoring.svc.cluster.local

If you set port-forwarding, access to the URL below on a client computer in your local network.

⇒ http://(Control Plane Node Hostname or IP address):(setting port)/

That's OK if following Prometheus UI is displayed.

[5]

If you access to Grafana from a Host in cluster, access to the URL below with an Web browser.

⇒ http://grafana.monitoring.svc.cluster.local

If you set port-forwarding, access to the URL below on a client computer in your local network.

⇒ http://(Control Plane Node Hostname or IP address):(setting port)/

That's OK if following Grafana UI is displayed.

For [admin] password, it's possible to confirm with the command below.
⇒ echo "Password: $(kubectl get secret grafana-admin --namespace monitoring -o jsonpath="{.data.GF_SECURITY_ADMIN_PASSWORD}" | base64 -d)"

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