Kubernetes increase resources for all deployments

Question

I am new to Kubernetes. I have a K8 cluster with multiple deployments (more than 150), each having more than 4 pods scaled. I have a requirement to increase resource limits for all deployments in the cluster; and I'm aware I can increase this directly via my deployment YAML. However, I'm thinking if there is any way I can increase the resources for all deployments at one go.

Thanks for your help in advance.

Answer 1

There are few things to point out here:

1. There is a kubectl patch command that allows you to:

Update field(s) of a resource using strategic merge patch, a JSON merge patch, or a JSON patch.

JSON and YAML formats are accepted.

See examples below:

kubectl patch deploy deploy1 deploy2 --type json -p='[{"op": "replace", "path": "/spec/template/spec/containers/0/resources/limits/memory", "value":"120Mi"}]'

or:

kubectl patch deploy $(kubectl get deploy -o go-template --template '{{range .items}}{{.metadata.name}}{{" "}}{{end}}') --type json -p='[{"op": "replace", "path": "/spec/template/spec/containers/0/resources/limits/memory", "value":"120Mi"}]'

For further reference see this doc.

2. You can add proper labels into deployment via kubectl set command:

---

kubectl set resources deployment -l key=value --limits memory=120Mi

3. Also, you can use some additional CLI like sed, awk or xargs. For example:

---

kubectl get deployments -o name | sed -e 's/.*\///g' | xargs -I {} kubectl patch deployment {} --type=json -p='[{"op": "replace", "path": "/spec/template/spec/containers/0/imagePullPolicy", "value": "Always"}]'

or:

kubectl get deployments -o name | awk '{print $1 }' | xargs kubectl patch deployment $0  -p "{\"spec\":{\"template\":{\"metadata\":{\"annotations\":{\"date\":\"`date +'%s'`\"}}}}}"

4. It is also worth noting that configuration files should be stored in version control before being pushed to the cluster. See the Configuration Best Practices for more details.

Answer 2

You can use kustomize's "components" system if you want to set them all to the same thing. But that's unlikely. Better solution is probably write a little Python (or whatever lang you prefer) script to modify all the YAML files and push them back into source control.