Ensure that the 'on-failure' container restart policy is set to '5'

LowLevel 1Automateddocker

Description

Restart policy 'always' (or on-failure with unlimited retries) can hide failures and turn a crashing container into a resource drain; on-failure with at most 5 retries is recommended. Flags always, unless-stopped and on-failure with 0 or more than 5 retries. The audit inspects every running container (docker ps -q) and prints the offending names; a host with no running containers is compliant.

How it is checked

Audit method: Shell command

shell

ids=$(docker ps -q) || exit 1; [ -z "$ids" ] && { echo compliant; exit 0; }; out=$(docker inspect --format '{{.Name}} {{.HostConfig.RestartPolicy.Name}} {{.HostConfig.RestartPolicy.MaximumRetryCount}}' $ids) || exit 1; bad=$(printf '%s\n' "$out" | awk '$2=="always" || $2=="unless-stopped" || ($2=="on-failure" && ($3+0==0 || $3+0>5)){print $1" "$2":"$3}'); [ -z "$bad" ] && echo compliant || printf '%s\n' "$bad"

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Redeploy with --restart=on-failure:5 (compose: 'restart: on-failure:5') or update in place: docker update --restart=on-failure:5 <container>.

Properties

Operating systems: Any
Tags: dockerruntime
Reference: CIS Docker Benchmark v1.9.0 - 5.15 Ensure that the 'on-failure' container restart policy is set to '5'

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target docker