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ci: Handle concurrent deletions in CI #696

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f59d0c6
ci: Remove unused snapshot_id from AMI cleanup
ystros Jul 27, 2026
2d79b18
ci: Handle deletion if AMI is missing
ystros Jul 27, 2026
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42 changes: 26 additions & 16 deletions ci/tasks/light-aws/cleanup-ami.sh
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Expand Up @@ -30,6 +30,28 @@ if [ -n "${ami_role_arn:-}" ]; then
export AWS_PROFILE=resource_account
fi

# Every stemcell pipeline runs the published sweep against the same account, so two
# pipelines can select the same AMI before either has deleted it. This handles
# expected potential errors that could occur on a collision.
delete_tolerating_missing() {

@Alphasite Alphasite Jul 27, 2026

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nit: should this be named something like: run_tolerate_missing_errors or something that doesn't specifically mention delete since its also used for deregister.

local output
if output="$("$@" 2>&1)"; then
[ -n "${output}" ] && echo "${output}"

@Alphasite Alphasite Jul 27, 2026

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nit: echo should probably be printf

return 0
fi

case "${output}" in
*InvalidAMIID.Unavailable*|*InvalidAMIID.NotFound*|*InvalidSnapshot.NotFound*)

@Alphasite Alphasite Jul 27, 2026

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gemini seems to think there is 1 more condition which may be worth a looksie at:

InvalidSnapshot.InUse Race Condition
When multiple pipelines are sweeping AMIs, they usually follow two steps:

  1. Deregister the AMI.
  2. Delete the underlying EBS Snapshots.

Because AWS is eventually consistent, if Pipeline A deregisters the AMI, AWS takes a few moments to "unlock" the underlying snapshot. If Pipeline B hits the snapshot deletion step during this window, AWS will throw InvalidSnapshot.InUse (not NotFound). If this function doesn't tolerate InUse in a concurrent environment, Pipeline B will fail completely.

echo " already deleted by another run, skipping"
return 0
;;
*)
echo "${output}" >&2
return 1
;;
esac
}

past_due=$(date --date="${ami_older_than_days} days ago" +"%Y-%m-%d")
# shellcheck disable=SC2016
past_due_query='sort_by(Images,&CreationDate)[?CreationDate<`'"${past_due}"'`].{ImageId: ImageId, date:CreationDate, SnapshotId: BlockDeviceMappings[0].Ebs.SnapshotId,Version: Tags[?Key==`name`]|[0].Value}'
Expand Down Expand Up @@ -59,16 +81,6 @@ for region in ${ami_destinations}; do
ami_list=$(jq -s '.[0] + .[1]' <(echo "${ami_list}") <(echo "${results}"))
fi

if [ -n "${snapshot_id:-}" ]; then
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results=$(aws ec2 describe-images \
--owners self \
--output json \
--region "${region}" \
--filters "Name=block-device-mapping.snapshot-id,Values=${snapshot_id}" \
--query "${past_due_query}" | jq 'reverse | del(.[range(env.ami_keep_latest|tonumber)])')
ami_list=$(jq -s '.[0] + .[1]' <(echo "${ami_list}") <(echo "${results}"))
fi

# 'ami_list' is a json array of objects, each object is an ami and its snapshot
for row in $(echo "${ami_list}" | jq -r '.[] | @base64'); do
_jq() {
Expand All @@ -83,14 +95,12 @@ for region in ${ami_destinations}; do
Snapshot id: $(_jq '.SnapshotId')
"

aws ec2 deregister-image \
delete_tolerating_missing aws ec2 deregister-image \
--image-id "$(_jq '.ImageId')" \
--region "${region}"

if [ "${snapshot_id:-}" != "$(_jq '.SnapshotId')" ]; then
aws ec2 delete-snapshot \
--snapshot-id "$(_jq '.SnapshotId')" \
--region "${region}"
fi
delete_tolerating_missing aws ec2 delete-snapshot \
--snapshot-id "$(_jq '.SnapshotId')" \
--region "${region}"
done
done
1 change: 0 additions & 1 deletion ci/tasks/light-aws/cleanup-ami.yml
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Expand Up @@ -14,5 +14,4 @@ params:
ami_older_than_days: "60" # Number of days AMI to keep excluding those currently being running
ami_keep_latest: "5" # Number of previous AMI to keep excluding those currently being running
os_name: "" # e.g ubuntu-jammy
snapshot_id: "" # Snapshot id to delete
remove_public_images: "false"
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