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Check component-status

Check command component-status is used to check status of Kubernetes components. Returns OK if components are Healthy, otherwise, returns Critical.

Spec

component-status has the following variables:

• selector - Label selector for components whose existence are checked.
• componentName - Name of Kubernetes component whose existence is checked.

Execution of this command can result in following states:

• OK
• Critical
• Unknown

Tutorial

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube.

Now, install Searchlight operator in your cluster following the steps here.

To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial. Run the following command to prepare your cluster for this tutorial:

$ kubectl create namespace demo
namespace "demo" created

$ kubectl get namespaces
NAME          STATUS    AGE
default       Active    6h
kube-public   Active    6h
kube-system   Active    6h
demo          Active    4m

Check status of all components

In this tutorial, we are going to create a ClusterAlert to check status of all components.

$ cat ./docs/examples/cluster-alerts/component-status/demo-0.yaml

apiVersion: monitoring.appscode.com/v1alpha1
kind: ClusterAlert
metadata:
  name: component-status-demo-0
  namespace: demo
spec:
  check: component-status
  checkInterval: 30s
  alertInterval: 2m
  notifierSecretName: notifier-config
  receivers:
  - notifier: Mailgun
    state: Critical
    to: ["ops@example.com"]

$ kubectl apply -f ./docs/examples/cluster-alerts/component-status/demo-0.yaml
clusteralert "component-status-demo-0" created

$ kubectl describe clusteralert -n demo component-status-demo-0
Name:		component-status-demo-0
Namespace:	demo
Labels:		<none>
Events:
  FirstSeen	LastSeen	Count	From			SubObjectPath	Type		Reason		Message
  ---------	--------	-----	----			-------------	--------	------		-------
  6s		6s		1	Searchlight operator			Normal		SuccessfulSync	Applied ClusterAlert: "component-status-demo-0"

Voila! component-status command has been synced to Icinga2. Please visit here to learn how to configure notifier secret. Now, open IcingaWeb2 in your browser. You should see a Icinga host demo@cluster and Icinga service component-status-demo-0.

Check status of a specific component

In this tutorial, a ClusterAlert will be used check status of a component by name by setting spec.componentName field.

$ cat ./docs/examples/cluster-alerts/component-status/demo-1.yaml

apiVersion: monitoring.appscode.com/v1alpha1
kind: ClusterAlert
metadata:
  name: component-status-demo-1
  namespace: demo
spec:
  check: component-status
  vars:
    componentName: etcd-0
  checkInterval: 30s
  alertInterval: 2m
  notifierSecretName: notifier-config
  receivers:
  - notifier: Mailgun
    state: Critical
    to: ["ops@example.com"]

$ kubectl apply -f ./docs/examples/cluster-alerts/component-status/demo-1.yaml
clusteralert "component-status-demo-1" created

$ kubectl describe clusteralert -n demo component-status-demo-1
Name:		component-status-demo-1
Namespace:	demo
Labels:		<none>
Events:
  FirstSeen	LastSeen	Count	From			SubObjectPath	Type		Reason		Message
  ---------	--------	-----	----			-------------	--------	------		-------
  22s		22s		1	Searchlight operator			Normal		SuccessfulSync	Applied ClusterAlert: "component-status-demo-1"

Pause Alert

To pause alert, edit ClusterAlert component-status-demo-1 to set spec.paused to be true

$ kubectl edit clusteralert component-status-demo-1 -n demo

spec:
  pause: true

Searchlight operator will delete Icinga Services for this alert. To resume, edit and set spec.paused to be false

Cleaning up

To cleanup the Kubernetes resources created by this tutorial, run:

$ kubectl delete ns demo

If you would like to uninstall Searchlight operator, please follow the steps here.

Next Steps

• To periodically run various checks on nodes in a Kubernetes cluster, use NodeAlerts.
• To periodically run various checks on pods in a Kubernetes cluster, use PodAlerts.
• See the list of supported notifiers here.
• Wondering what features are coming next? Please visit here.
• Want to hack on Searchlight? Check our contribution guidelines.