check_docker

Nagios/NRPE compatible plugins for checking docker based services. Currently there are two nagios checks

• check_docker which checks docker container health
• check_swarm which checks health of swarm nodes and services

With check_docker can use it to check and alert on

• memory consumption in absolute units (bytes, kb, mb, gb) and as a percentage (0-100%) of the container limit.
• CPU usages as a percentage (0-100%) of container limit.
• automatic restarts performed by the docker daemon
• container status, i.e. is it running?
• container health checks are passing?
• uptime, i.e. is it able to stay running for a long enough time?
• the presence of a container or containers matching specified names
• image version, does the running image match that in the remote registry?
• image age, when was the image built the last time?

With check_swarm you can alert

• if a node is not joined to a docker swarm
• if a service is running in a swarm

These checks can communicate with a local docker daemon socket file (default) or with local or remote docker daemons using secure and non-secure TCP connections.

These plugins require python 3. It is tested on 3.5 and greater but may work on older versions of 3.

Installation

With pip

pip3 install check_docker
--or--
pip install check_docker

With curl

curl -o /usr/local/bin/check_docker https://raw.githubusercontent.com/timdaman/check_docker/master/check_docker/check_docker.py
curl -o /usr/local/bin/check_swarm https://raw.githubusercontent.com/timdaman/check_docker/master/check_docker/check_swarm.py
chmod a+rx /usr/local/bin/check_docker /usr/local/bin/check_swarm

With wget

wget -O /usr/local/bin/check_docker https://raw.githubusercontent.com/timdaman/check_docker/master/check_docker/check_docker.py
wget -O /usr/local/bin/check_swarm https://raw.githubusercontent.com/timdaman/check_docker/master/check_docker/check_swarm.py
chmod a+rx /usr/local/bin/check_docker /usr/local/bin/check_swarm

check_docker Usage

usage: check_docker.py [-h]
                       [--connection [/<path to>/docker.socket|<ip/host address>:<port>]
                       | --secure-connection [<ip/host address>:<port>]]
                       [--binary_units | --decimal_units] [--timeout TIMEOUT]
                       [--containers CONTAINERS [CONTAINERS ...]] [--present]
                       [--threads THREADS] [--cpu WARN:CRIT]
                       [--memory WARN:CRIT:UNITS] [--status STATUS] [--health]
                       [--uptime WARN:CRIT] [--image-age WARN:CRIT] [--version]
                       [--insecure-registries INSECURE_REGISTRIES [INSECURE_REGISTRIES ...]]
                       [--restarts WARN:CRIT] [--no-ok] [--no-performance] [-V]

Check docker containers.

optional arguments:
  -h, --help            show this help message and exit
  --connection [/<path to>/docker.socket|<ip/host address>:<port>]
                        Where to find docker daemon socket. (default:
                        /var/run/docker.sock)
  --secure-connection [<ip/host address>:<port>]
                        Where to find TLS protected docker daemon socket.
  --binary_units        Use a base of 1024 when doing calculations of KB, MB,
                        GB, & TB (This is default)
  --decimal_units       Use a base of 1000 when doing calculations of KB, MB,
                        GB, & TB
  --timeout TIMEOUT     Connection timeout in seconds. (default: 10.0)
  --containers CONTAINERS [CONTAINERS ...]
                        One or more RegEx that match the names of the
                        container(s) to check. If omitted all containers are
                        checked. (default: ['all'])
  --present             Modifies --containers so that each RegEx must match at
                        least one container.
  --threads THREADS     This + 1 is the maximum number of concurent
                        threads/network connections. (default: 10)
  --cpu WARN:CRIT       Check cpu usage percentage taking into account any
                        limits. Valid values are 0 - 100.
  --memory WARN:CRIT:UNITS
                        Check memory usage taking into account any limits.
                        Valid values for units are %,B,KB,MB,GB.
  --status STATUS       Desired container status (running, exited, etc).
  --health              Check container's health check status
  --uptime WARN:CRIT    Minimum container uptime in seconds. Use when
                        infrequent crashes are tolerated.
  --image-age WARN:CRIT Maximum image age in days.
  --version             Check if the running images are the same version as
                        those in the registry. Useful for finding stale
                        images. Does not support login.
  --insecure-registries INSECURE_REGISTRIES [INSECURE_REGISTRIES ...]
                        List of registries to connect to with http(no TLS).
                        Useful when using "--version" with images from
                        insecure registries.
  --restarts WARN:CRIT  Container restart thresholds.
  --no-ok               Make output terse suppressing OK messages. If all
                        checks are OK return a single OK.
  --no-performance      Suppress performance data. Reduces output when
                        performance data is not being used.
  -V                    show program's version number and exit

check_swarm Usage

usage: check_swarm.py [-h]
                      [--connection [/<path to>/docker.socket|<ip/host address>:<port>]
                      | --secure-connection [<ip/host address>:<port>]]
                      [--timeout TIMEOUT]
                      (--swarm | --service SERVICE [SERVICE ...] | --ignore_paused)
                      [-V]

Check docker swarm.

optional arguments:
  -h, --help            show this help message and exit
  --connection [/<path to>/docker.socket|<ip/host address>:<port>]
                        Where to find docker daemon socket. (default:
                        /var/run/docker.sock)
  --secure-connection [<ip/host address>:<port>]
                        Where to find TLS protected docker daemon socket.
  --timeout TIMEOUT     Connection timeout in seconds. (default: 10.0)
  --swarm               Check swarm status
  --service SERVICE [SERVICE ...]
                        One or more RegEx that match the names of the
                        services(s) to check.
  --ignore_paused       Don't require global services to be running on paused nodes
  -V                    show program's version number and exit

Gotchas

• When using check_docker with older versions of docker (I have seen 1.4 and 1.5) –status only supports ‘running’, ‘restarting’, and ‘paused’.
• When using check_docker, if no container is specified, all containers are checked. Some containers may return critcal status if the selected check(s) require a running container.
• When using check_docker, --present cannot be used without --containers to indicate what to check the presence of.