2 min read
Some kubernetes objects creates and manages other kubernetes objects in order to provide it's functionality. For example, the Deployment object creates a ReplicaSet that in turn creates the desired Pod objects. We can always track down this relationship using kubectl describe but using the tree krew plugin we can see the relationship in a visual way. We can install it like so:
$ kubectl krew install tree
14/06/2021
Read more...2 min read
When performing rolling updates we can see it's history using kubectl rollout history:
$ kubectl rollout history deploy pet2cattle
deployment.apps/pet2cattle
REVISION CHANGE-CAUSE
100 <none>
101 <none>
102 <none>
103 <none>
104 <none>
105 <none>
106 <none>
107 <none>
109 kubectl scale deployment/pet2cattle --replicas=2 --record=true
110 kubectl scale deployment/pet2cattle --replicas=5 --record=true
111 kubectl scale deployment/pet2cattle --replicas=1 --record=true
If have any problem with the update we can undo and update using kubectl rollout undo
25/05/2021
Read more...2 min read
To change a container's image we can:
Let's check how to use kubectl set image
14/05/2021
Read more...2 min read
When we want to access services that run inside a kubernetes cluster that are not supposed to be normally accessed we can temporally run kubectl port-forward to forward traffic to our workstation. To be able to use it, the node must have socat installed.
13/05/2021
Read more...1 min read
Using kubectl drain you can evict pods and disabled scheduling for a node so you can proceed with some maintenance. Once this maintenance is over we will need to allow pods to be scheduled to this node, removing the SchedulingDisabled:
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
nauvoo.pet2cattle.com Ready control-plane,master 19d v1.20.4+k3s1
tycho.pet2cattle.com Ready,SchedulingDisabled <none> 9m25s v1.20.4+k3s1
29/04/2021
Read more...