Set draino/drain-buffer

ej-k8s-set-drain-buffer.sh

#!/bin/bash

# See https://github.com/DataDog/k8s-resources/pull/33140
# See https://datadoghq.atlassian.net/wiki/spaces/K8S/pages/2277966820/NLA+-+FAQ#%5BinlineExtension%5DHow-can-I-slow-down-the-pace-of-node-rotation-for-my-nodegroup-%3F

# We want to set draino/drain-buffer to a fixed value, for all clusters.
# Currently NLA/Draino is only on us3.prod.dog.

BUFFERVAL=9h
FPATCH=/tmp/tmp_patch.yaml
FPATCHJSON=/tmp/tmp_patch.json

set -e

kubectx plain4.us3.prod.dog

update_one() {
    ns=$1
    ng=$2

    echo "$ns $ng"

    # Kubelet: Annotations: draino/drain-buffer:

    # Outputs all annotations. We just one the one for drain-buffer.
    kubectl get ng -n $ns $ng -o=jsonpath="{.spec.kubelet.annotations}" | jq
    # kubectl get ng -n $ns $ng -o yaml | grep "draino/drain-buffer"

    # https://github.com/kubernetes/kubernetes/issues/37666
    # Cannot use annotate because we want a nested element.
    # kubectl annotate ng -n $ns $ng --overwrite "draino/drain-buffer=$BUFFERVAL"


    # kubectl annotate ng -n $ns $ng --overwrite "draino/drain-buffer=$BUFFERVAL"
    # echo '{"spec":{"kubelet":{"annotations":{"draino/drain-buffer": "'${BUFFERVAL}'" }}}}' >$FPATCH

    if false; then
        # Try using a file.
        # Tried lowercase, and tried mixed case, did not seem to make a difference.
        echo "Spec:" >$FPATCH
        echo "  Kubelet:" >>$FPATCH
        echo "    Annotations:" >>$FPATCH
        echo "      draino/drain-buffer: \"$BUFFERVAL\"" >>$FPATCH
        # echo "      draino/drain-buffer: $BUFFERVAL" >>$FPATCH
        cat $FPATCH

        # kubectl patch -n $ns ng $ng --patch-file $FPATCH --type=merge
        # kubectl patch -n $ns ng $ng --patch-file $FPATCH # Gives error
        # --type=merge does not give error, but did not save either

        # kubectl patch -n $ns ng $ng --patch-file $FPATCH --type strategic
        # Error from server (UnsupportedMediaType): the body of the request was in an unknown format - accepted media types include: application/json-patch+json, application/merge-patch+json, application/apply-patch+yaml
        # If I understand right from one of the bugs, we cannot use strategic merge for an internal nested resource or something like that.
        # kubectl patch -n $ns ng $ng --patch-file $FPATCH --type merge

        kubectl patch -n $ns ng $ng --patch-file $FPATCH --dry-run=server
        # Error from server (UnsupportedMediaType): the body of the request was in an unknown format - accepted media types include: application/json-patch+json, application/merge-patch+json, application/apply-patch+yaml

        # Maybe this problem: 
        # https://github.com/redhat-cop/resource-locker-operator/issues/63
        # https://github.com/argoproj/argo-rollouts/issues/161
    fi

    if false; then
        # Use a json file. Note that we give directions for what to do in the json.
        echo "- op: replace" >$FPATCH
        echo "  path: \"/spec/kubelet/annotations/draino/drain-buffer\"" >>$FPATCH
        # echo "  path: \"/spec/kubelet/annotations/draino//drain-buffer\"" >>$FPATCH
        # echo "  path: \"/spec/kubelet/annotations/draino\\/drain-buffer\"" >>$FPATCH
        # echo "  value: \"$BUFFERVAL\"" >>$FPATCH
        echo "  value: $BUFFERVAL" >>$FPATCH
        cat $FPATCH

        kubectl patch -n $ns ng $ng --patch-file $FPATCH --type=json --dry-run=server
        # The request is invalid.
        # kubectl patch -n $ns ng $ng --patch-file $FPATCH --type=json
        # The request is invalid.
    fi

    if false; then
        echo '{"spec":{"kubelet":{"annotations":{"draino/drain-buffer": "'${BUFFERVAL}'" }}}}' >$FPATCH
        cat $FPATCH
        kubectl patch -n $ns ng $ng --patch-file $FPATCH --type=json
        # Error from server (BadRequest): json: cannot unmarshal object into Go value of type jsonpatch.Patch

        # echo '{"kubelet":{"annotations":{"draino/drain-buffer": "'${BUFFERVAL}'" }}}' >$FPATCH
        # cat $FPATCH
        # kubectl patch -n $ns ng $ng --patch-file $FPATCH --type json
        # Error from server (BadRequest): json: cannot unmarshal object into Go value of type jsonpatch.Patch
    fi

    if false; then
        # kubectl patch -n $ns ng $ng --patch '{"spec":{"kubelet":{"annotations":{"draino/drain-buffer": "11h" }}}}'
        # Error from server (UnsupportedMediaType): the body of the request was in an unknown format - accepted media types include: application/json-patch+json, application/merge-patch+json, application/apply-patch+yaml

        kubectl patch -n $ns ng $ng --type='json' --patch '{"spec":{"kubelet":{"annotations":{"draino/drain-buffer": "11h" }}}}'
        # Error from server (UnsupportedMediaType): the body of the request was in an unknown format - accepted media types include: application/json-patch+json, application/merge-patch+json, application/apply-patch+yaml
    fi

    if false; then
        # Try []
        kubectl patch -n $ns ng $ng --dry-run=server --type='json' --patch '{"spec":{"kubelet":{"annotations":[{"draino/drain-buffer": "11h" }]}}}'
        # Error from server (BadRequest): json: cannot unmarshal object into Go value of type jsonpatch.Patch
    fi

    if false; then
        kubectl patch -n $ns ng $ng --dry-run=server --type='json' --patch '{"spec":{"kubelet":{"annotations":{"draino/drain-buffer": "11h" }}}}'
        # Error from server (BadRequest): json: cannot unmarshal object into Go value of type jsonpatch.Patch
    fi

    if true; then
        kubectl patch -n $ns ng $ng --dry-run=server --type=strategic --patch '{"spec":{"kubelet":{"annotations":{"draino/drain-buffer": "11h" }}}}'
        # Error from server (UnsupportedMediaType): the body of the request was in an unknown format - accepted media types include: application/json-patch+json, application/merge-patch+json, application/apply-patch+yaml
    fi


    kubectl get ng -n $ns $ng -o=jsonpath="{.spec.kubelet.annotations}" | jq
    # kubectl get ng -n $ns $ng -o yaml | grep "draino/drain-buffer"
}

update_one cassandra-hosts cassandra-hosts

# kubectl get ng -l service=cassandra -A --no-headers | while read -r ns ng junk; do
#     update_one $ns $ng
# done