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>
This fix tries to fix the discrepancy between API and CLI on hostname
validation. Previously, the hostname validation was handled at the
CLI interface in runconfig/opts/parse.go and return an error if the
hostname is invalid. However, if an end user use the remote API to
pass the hostname, the error will not be returned immediately.
Instead the error will only be thrown out when the container creation
fails. This creates behavior discrepancy between API and CLI.
In this fix, the hostname validation was moved to
verifyContainerSettings so the behavior will be the same for API and
CLI.
After the change, since CLI does not handle the hostname validation
any more, the previous unit tests about hostname validation on CLI
in runconfig/opts/parse_test.go has to be updated as well because
there is no validation at this stage. All those unit tests are moved
to integration test TestRunTooLongHostname so that the hostname
validation is still properly covered as before.
Note: Since the hostname validation moved to API, the error message
changes from `invalid hostname format for --hostname:` to
`invalid hostname format:` as well because `--hostname` is passed
to CLI only.
This fix fixes#21595.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
This fix tries to fix issues encountered when running a container with a hostname
that is longer than HOST_NAME_MAX(64).
Previously, `could not synchronise with container process` was generated as the
length of the regex check was missing.
This fix covers the length check so that a hostname that is longer than
HOST_NAME_MAX(64) will be given a correct error message.
Several unit tests cases and additional integration test cases are added as well.
This fix closes#21445.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
The issue comes from the implementation of volumeSplitN() where a
driver letter (`[a-zA-Z]:`) was assumed to follow either `:`, `/`,
or `\\`.
In Windows driver letter appears in two situations:
a. `^[a-zA-Z]:` (A colon followed by `^[a-zA-Z]:` is OK as colon is
the separator in volume option)
b. A string in the format like `\\?\C:\Windows\...` (UNC).
Therefore, a driver letter can only follow either a `:` or `\\`
This PR removes the condition of `/` before the driver letter so
that options like `-v /tmp/q:/foo` could be handled correctly. A
couple of tests has also been added.
This PR fixes#20122.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Validates whether the given hostname is RFC 1123
(https://tools.ietf.org/html/rfc1123) compliant.
Fixes#20371
Signed-off-by: Andrew Guenther <guenther.andrew.j@gmail.com>
This allows users to provide a FQDN as hostname or to use distinct hostname and
domainname parts. Depends on https://github.com/docker/libnetwork/pull/950
Signed-off-by: Tim Hockin <thockin@google.com>
dockerfile.Config is almost redundant with ImageBuildOptions.
Unify the two so that the latter can be removed. This also
helps build's API endpoint code to be less dependent on package
dockerfile.
Signed-off-by: Anusha Ragunathan <anusha@docker.com>
The parse.go file is used almost exclusively in the client. The few small
functions that are used outside of the client could easily be copied out
when the client is extracted, allowing this runconfig/opts package to
move to the client.
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2016-01-04 12:06:29 -05:00
Renamed from runconfig/client/parse_test.go (Browse further)
