This PR adds support for user-defined health-check probes for Docker
containers. It adds a `HEALTHCHECK` instruction to the Dockerfile syntax plus
some corresponding "docker run" options. It can be used with a restart policy
to automatically restart a container if the check fails.
The `HEALTHCHECK` instruction has two forms:
* `HEALTHCHECK [OPTIONS] CMD command` (check container health by running a command inside the container)
* `HEALTHCHECK NONE` (disable any healthcheck inherited from the base image)
The `HEALTHCHECK` instruction tells Docker how to test a container to check that
it is still working. This can detect cases such as a web server that is stuck in
an infinite loop and unable to handle new connections, even though the server
process is still running.
When a container has a healthcheck specified, it has a _health status_ in
addition to its normal status. This status is initially `starting`. Whenever a
health check passes, it becomes `healthy` (whatever state it was previously in).
After a certain number of consecutive failures, it becomes `unhealthy`.
The options that can appear before `CMD` are:
* `--interval=DURATION` (default: `30s`)
* `--timeout=DURATION` (default: `30s`)
* `--retries=N` (default: `1`)
The health check will first run **interval** seconds after the container is
started, and then again **interval** seconds after each previous check completes.
If a single run of the check takes longer than **timeout** seconds then the check
is considered to have failed.
It takes **retries** consecutive failures of the health check for the container
to be considered `unhealthy`.
There can only be one `HEALTHCHECK` instruction in a Dockerfile. If you list
more than one then only the last `HEALTHCHECK` will take effect.
The command after the `CMD` keyword can be either a shell command (e.g. `HEALTHCHECK
CMD /bin/check-running`) or an _exec_ array (as with other Dockerfile commands;
see e.g. `ENTRYPOINT` for details).
The command's exit status indicates the health status of the container.
The possible values are:
- 0: success - the container is healthy and ready for use
- 1: unhealthy - the container is not working correctly
- 2: starting - the container is not ready for use yet, but is working correctly
If the probe returns 2 ("starting") when the container has already moved out of the
"starting" state then it is treated as "unhealthy" instead.
For example, to check every five minutes or so that a web-server is able to
serve the site's main page within three seconds:
HEALTHCHECK --interval=5m --timeout=3s \
CMD curl -f http://localhost/ || exit 1
To help debug failing probes, any output text (UTF-8 encoded) that the command writes
on stdout or stderr will be stored in the health status and can be queried with
`docker inspect`. Such output should be kept short (only the first 4096 bytes
are stored currently).
When the health status of a container changes, a `health_status` event is
generated with the new status. The health status is also displayed in the
`docker ps` output.
Signed-off-by: Thomas Leonard <thomas.leonard@docker.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Upstream-commit: b6c7becbfe1d76b1250f6d8e991e645e13808a9c
Component: engine
"copy" can be misleading for humans because Go has its own builtin "copy" function
Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Upstream-commit: 8bce6265fca22c117cf6d69d9ffd4ee78da9db8a
Component: engine
Now daemon/logger.Copier does not use ContainerID
Addendum to #23141
Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Upstream-commit: 518709a87e04f55babc5162861aa4ba9a423f0c8
Component: engine
Add reference to https://github.com/vmware/docker-volume-vsphere to Docker's list of plugins.
This is an officially supported plugin from VMware.
Signed-off-by: Ritesh H Shukla <sritesh@vmware.com>
Upstream-commit: f5df49b3dcfeb1164ca60d4dbf7756603e61a299
Component: engine
This fix updates remote API docs for the removal of deprecated `force` in `docker tag`.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Upstream-commit: 7b08941882668c1c40adb03d9227d22e0aa5e605
Component: engine
The -f flag on docker tag has been deprecated in docker 1.10 and
is expected to be removed in docker 1.12.
This fix removed the -f flag on docker tag and also updated
deprecated.md.
NOTE: A separate pull request for engine-api has been opened to
cover the related changes.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Upstream-commit: 4455ec14b87d5ad474c5e11d60907bceb35e9e09
Component: engine
This fix updates engine-api to 6facb3f3c38717b8f618dcedc4c8ce20d1bfc61e.
This fix is related to #23090.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Upstream-commit: 1dab9af5d5acc1fe3a1bfb84a5cc576d664095e4
Component: engine
This does a minor cleanup of the logging driver
documentation;
- Add a table-header to the driver-options
table.
- Add language hints to code-blocks to
prevent incorrect highlighting
- Wrap some code examples so that they
fit in the default layout
- Wrap text to 80-chars
- Fix ordering in menu
- Some minor rewording
We should still create separate pages
for all available drivers (for example,
json-file, syslog, and GELF don't have
their own configuration page)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Upstream-commit: a9f6d93099283ee06681caae7fe29bd1b2dd4c77
Component: engine
