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.

Doubleheader

You can try Vertical Pod Autoscaler with "Auto" mode? – Coady

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.

Trouveur

Does anyone know how to adapt this to also include the namespace? I.E. have kubectl patch all deployments in all (or multiple) namespaces? I tried it with the 2nd one, but how can I pass the relationship between deployment name and namespace out of the $() properly? – Necromancy

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.

Bogus