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Watch node object for podCIDR instead of crash + wait for restart #329

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merged 1 commit into from
May 27, 2024
Merged

Watch node object for podCIDR instead of crash + wait for restart #329

merged 1 commit into from
May 27, 2024

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jingyuanliang
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@jingyuanliang jingyuanliang commented May 24, 2024 •
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This can save up to 10 seconds before Kubelet decides to restart the pod after the crash.

Also made some logging improvements.

/assign @marqc
/assign @sypakine
/hold

@jingyuanliang jingyuanliang changed the title Watch node object for podCIDR instead of crashing and wait for restart Watch node object for podCIDR instead of crash + wait for restart May 24, 2024
@google-oss-prow google-oss-prow bot added size/L and removed size/S labels May 24, 2024
marqc
marqc suggested changes May 24, 2024
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scripts/install-cni.sh Outdated
host=${KUBERNETES_SERVICE_HOST}
# If host contains a colon (:), it is an IPv6 address, hence needs wrapping
# with [..].
if [[ "${host}" =~ : ]]; then
host="[$host]"
fi
node_url="https://$host:${KUBERNETES_SERVICE_PORT}/api/v1/nodes/${HOSTNAME}"
response=$(curl -k -s -H "Authorization: Bearer $token" "$node_url")
node_url="https://$host:${KUBERNETES_SERVICE_PORT}/api/v1/watch/nodes/${HOSTNAME}"
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The /api/v1/watch/nodes path is deprecated:

watch changes to an object of kind Node. deprecated: use the 'watch' parameter with a list operation instead, filtered to a single item with the 'fieldSelector' parameter.

https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.26/#node-v1-core

Please use the recommended approach for the list with fieldSelector for metadata.name field equal to the hostname.

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Done

scripts/install-cni.sh Outdated
response=$(curl -k -s -H "Authorization: Bearer $token" "$node_url")
node_url="https://$host:${KUBERNETES_SERVICE_PORT}/api/v1/watch/nodes/${HOSTNAME}"
for _ in {1..3}; do
response=$(grep -m1 . <(curl -k -s -N -H "Authorization: Bearer $(</var/run/secrets/kubernetes.io/serviceaccount/token)" "$node_url" | jq --unbuffered -c '.object | select(.spec.podCIDR != null)'))
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there is no timeout specified, please specify the timeout explicitly using the timeoutSeconds request param to avoid the forever hanging call.

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Additionally you can add the limit=1 parameter to end the call as soon as the first update on the node object gets returned.

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Timeout added, and no, we can't end as soon as the first update, in case the first update is not adding podCIDR.

grep -m1 . <(...) can return after receiving the first line.

scripts/install-cni.sh Outdated
node_url="https://$host:${KUBERNETES_SERVICE_PORT}/api/v1/nodes/${HOSTNAME}"
response=$(curl -k -s -H "Authorization: Bearer $token" "$node_url")
node_url="https://$host:${KUBERNETES_SERVICE_PORT}/api/v1/watch/nodes/${HOSTNAME}"
for _ in {1..3}; do
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nit: 1..3 is a magic number. make it a named const variable that says this is the number of retries.

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Done.

scripts/install-cni.sh Outdated
fatal "Could not successfully watch node and wait for podCIDR."
fi
log "Node object fetched from $node_url"
log "${response}"
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This whole block may be extracted into the bash function for better readability, i.e. get_k8s_node_descriptor. And additionally the variable name can be changed to something more meaningful than $response

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The response is somehow used throughout the file... don't bother to change it for now.

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Actually, it's not too many. Let me change it and get the opportunity to change and poor styles along the way.

marqc
marqc reviewed May 24, 2024
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scripts/install-cni.sh Outdated
# for kubelet to retry the whole container if response is still not fetched.
fetch_node_object 3 20

if [[ -z "${node_object:-}" ]]; then
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this check and the following 2 log entries can be part of the fetch_node_object function as well

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Modified a bit, but I still like to leave the full dump outside.

@google-oss-prow google-oss-prow bot added the lgtm label May 24, 2024
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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jingyuanliang, marqc

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@google-oss-prow google-oss-prow bot removed the lgtm label May 24, 2024
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/hold cancel

@google-oss-prow google-oss-prow bot added size/XL and removed size/L labels May 24, 2024
@jingyuanliang
Watch node object for podCIDR instead of crash + wait for restart
68920f9 
This can save up to about 10 seconds (initial CrashLoopBackOff delay)
before Kubelet decides to restart the pod after the crash.
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marqc commented May 27, 2024

/lgtm

@google-oss-prow google-oss-prow bot added the lgtm label May 27, 2024
@google-oss-prow google-oss-prow bot merged commit 929f2bc into GoogleCloudPlatform:master May 27, 2024
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@marqc marqc marqc approved these changes

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