docker-scripts

Set of scripts to get useful information within docker containers.

Usage

All get_ scripts will print the requested information to stdout.

All is_ scripts will return exit code 0 if the condition is met, and 1 otherwise.

Any unexpected behavior will be printed to stderr.

If the VERBOSE environment variable is set to true, the scripts will print additional information to stderr.

Additionally, you can set the DEBUG environment variable to true to print debug information to stderr.

Installation

You can add the scripts to your images like this:

FROM alpine

ARG DOCKER_SCRIPTS_VERSION=0.2.0
ADD https://github.com/felipecrs/docker-scripts.git#v${DOCKER_SCRIPTS_VERSION}:scripts /opt/docker-scripts

And then, you can invoke any script calling it from /opt/docker-scripts:

❯ docker run --rm --cpus 2 my-image /opt/docker-scripts/get_cpus.sh
2

get_cpus.sh

In a system with cgroup v2:

❯ cat scripts/get_cpus.sh | docker run --rm -i -e VERBOSE=true alpine sh
VERBOSE(get_cpus.sh): cgroup v2 detected.
VERBOSE(get_cpus.sh): No CPU limits set.
VERBOSE(get_cpus.sh): CPUs:
16

❯ cat scripts/get_cpus.sh | docker run --rm -i -e VERBOSE=true --cpus 2 alpine sh
VERBOSE(get_cpus.sh): cgroup v2 detected.
VERBOSE(get_cpus.sh): CPUs:
2

❯ cat scripts/get_cpus.sh | docker run --rm -i -e VERBOSE=true --cpus 1.5 alpine sh
VERBOSE(get_cpus.sh): cgroup v2 detected.
VERBOSE(get_cpus.sh): CPUs:
1

❯ cat scripts/get_cpus.sh | docker run --rm -i -e VERBOSE=true --cpus 0.5 alpine sh
VERBOSE(get_cpus.sh): cgroup v2 detected.
VERBOSE(get_cpus.sh): CPUs:
1

Another system with cgroup v1:

❯ cat scripts/get_cpus.sh | docker run --rm -i -e VERBOSE=true alpine sh
VERBOSE(get_cpus.sh): cgroup v1 detected.
VERBOSE(get_cpus.sh): No CPU limits set.
VERBOSE(get_cpus.sh): CPUs:
8

❯ cat scripts/get_cpus.sh | docker run --rm -i -e VERBOSE=true --cpus 2 alpine sh
VERBOSE(get_cpus.sh): cgroup v1 detected.
VERBOSE(get_cpus.sh): CPUs:
2

❯ cat scripts/get_cpus.sh | docker run --rm -i -e VERBOSE=true --cpus 1.5 alpine sh
VERBOSE(get_cpus.sh): cgroup v1 detected.
VERBOSE(get_cpus.sh): CPUs:
1

❯ cat scripts/get_cpus.sh | docker run --rm -i -e VERBOSE=true --cpus 0.5 alpine sh
VERBOSE(get_cpus.sh): cgroup v1 detected.
VERBOSE(get_cpus.sh): CPUs:
1

get_memory.sh

In a system with cgroup v2:

❯ cat scripts/get_memory.sh | docker run --rm -i -e VERBOSE=true alpine sh
VERBOSE(get_memory.sh): cgroup v2 detected.
VERBOSE(get_memory.sh): No memory limits set.
VERBOSE(get_memory.sh): Memory (MB):
15996

❯ cat scripts/get_memory.sh | docker run --rm -i -e VERBOSE=true --memory 1g alpine sh
VERBOSE(get_memory.sh): cgroup v2 detected.
VERBOSE(get_memory.sh): Memory (MB):
1024

Another system with cgroup v1:

❯ cat scripts/get_memory.sh | docker run --rm -i -e VERBOSE=true alpine sh
VERBOSE(get_memory.sh): cgroup v1 detected.
VERBOSE(get_memory.sh): No memory limits set.
Memory (MB):
32092

❯ cat scripts/get_memory.sh | docker run --rm -i -e VERBOSE=true --memory 1g alpine sh
VERBOSE(get_memory.sh): cgroup v1 detected.
VERBOSE(get_memory.sh): Memory (MB):
1024

is_privileged.sh

❯ cat scripts/is_privileged.sh | docker run --rm -i -e VERBOSE=true alpine sh
VERBOSE(is_privileged.sh): Container is not running in privileged mode.
❯ echo $?
1

❯ cat scripts/is_privileged.sh | docker run --rm -i -e VERBOSE=true --privileged alpine sh
VERBOSE(is_privileged.sh): Container is running in privileged mode.
❯ echo $?
0