tyler.durden/compose
1
0
Fork 0
mirror of https://github.com/docker/compose.git synced 2025-07-08 14:24:26 +02:00
Code Issues Packages Projects Releases Wiki Activity
compose/docs/compose-file.md
Aanand Prasad e40de088f3 Document depends_on 
Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>
2016-01-26 11:52:21 +00:00

947 lines
26 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!--[metadata]>
+++
title = "Compose file reference"
description = "Compose file reference"
keywords = ["fig, composition, compose, docker"]
aliases = ["/compose/yml"]
[menu.main]
parent="smn_compose_ref"
+++
<![end-metadata]-->
# Compose file reference
The Compose file is a [YAML](http://yaml.org/) file defining
[services](#service-configuration-reference),
[networks](#network-configuration-reference) and
[volumes](#volume-configuration-reference).
The default path for a Compose file is `./docker-compose.yml`.
A service definition contains configuration which will be applied to each
container started for that service, much like passing command-line parameters to
`docker run`. Likewise, network and volume definitions are analogous to
`docker network create` and `docker volume create`.
As with `docker run`, options specified in the Dockerfile (e.g., `CMD`,
`EXPOSE`, `VOLUME`, `ENV`) are respected by default - you don't need to
specify them again in `docker-compose.yml`.
You can use environment variables in configuration values with a Bash-like
`${VARIABLE}` syntax - see [variable substitution](#variable-substitution) for
full details.
## Service configuration reference
> **Note:** There are two versions of the Compose file format – version 1 (the
> legacy format, which does not support volumes or networks) and version 2 (the
> most up-to-date). For more information, see the [Versioning](#versioning)
> section.
This section contains a list of all configuration options supported by a service
definition.
### build
Configuration options that are applied at build time.
`build` can be specified either as a string containing a path to the build
context, or an object with the path specified under [context](#context) and
optionally [dockerfile](#dockerfile) and [args](#args).
build: ./dir
build:
context: ./dir
dockerfile: Dockerfile-alternate
args:
buildno: 1
> **Note**: In the [version 1 file format](#version-1), `build` is different in
> two ways:
>
> - Only the string form (`build: .`) is allowed - not the object form.
> - Using `build` together with `image` is not allowed. Attempting to do so
> results in an error.
#### context
> [Version 2 file format](#version-2) only. In version 1, just use
> [build](#build).
Either a path to a directory containing a Dockerfile, or a url to a git repository.
When the value supplied is a relative path, it is interpreted as relative to the
location of the Compose file. This directory is also the build context that is
sent to the Docker daemon.
Compose will build and tag it with a generated name, and use that image thereafter.
build:
context: ./dir
#### dockerfile
Alternate Dockerfile.
Compose will use an alternate file to build with. A build path must also be
specified.
build:
context: .
dockerfile: Dockerfile-alternate
> **Note**: In the [version 1 file format](#version-1), `dockerfile` is
> different in two ways:
>
> - It appears alongside `build`, not as a sub-option:
>
> build: .
> dockerfile: Dockerfile-alternate
> - Using `dockerfile` together with `image` is not allowed. Attempting to do
> so results in an error.
#### args
> [Version 2 file format](#version-2) only.
Add build arguments. You can use either an array or a dictionary. Any
boolean values; true, false, yes, no, need to be enclosed in quotes to ensure
they are not converted to True or False by the YML parser.
Build arguments with only a key are resolved to their environment value on the
machine Compose is running on.
build:
args:
buildno: 1
user: someuser
build:
args:
- buildno=1
- user=someuser
### cap_add, cap_drop
Add or drop container capabilities.
See `man 7 capabilities` for a full list.
cap_add:
- ALL
cap_drop:
- NET_ADMIN
- SYS_ADMIN
### command
Override the default command.
command: bundle exec thin -p 3000
The command can also be a list, in a manner similar to [dockerfile](https://docs.docker.com/engine/reference/builder/#cmd):
command: [bundle, exec, thin, -p, 3000]
### cgroup_parent
Specify an optional parent cgroup for the container.
cgroup_parent: m-executor-abcd
### container_name
Specify a custom container name, rather than a generated default name.
container_name: my-web-container
Because Docker container names must be unique, you cannot scale a service
beyond 1 container if you have specified a custom name. Attempting to do so
results in an error.
### devices
List of device mappings. Uses the same format as the `--device` docker
client create option.
devices:
- "/dev/ttyUSB0:/dev/ttyUSB0"
### depends_on
Express dependency between services, which has two effects:
- `docker-compose up` will start services in dependency order. In the following
example, `db` and `redis` will be started before `web`.
- `docker-compose up SERVICE` will automatically include `SERVICE`'s
dependencies. In the following example, `docker-compose up web` will also
create and start `db` and `redis`.
version: 2
services:
web:
build: .
depends_on:
- db
- redis
redis:
image: redis
db:
image: postgres
### dns
Custom DNS servers. Can be a single value or a list.
dns: 8.8.8.8
dns:
- 8.8.8.8
- 9.9.9.9
### dns_search
Custom DNS search domains. Can be a single value or a list.
dns_search: example.com
dns_search:
- dc1.example.com
- dc2.example.com
### entrypoint
Override the default entrypoint.
entrypoint: /code/entrypoint.sh
The entrypoint can also be a list, in a manner similar to [dockerfile](https://docs.docker.com/engine/reference/builder/#entrypoint):
entrypoint:
- php
- -d
- zend_extension=/usr/local/lib/php/extensions/no-debug-non-zts-20100525/xdebug.so
- -d
- memory_limit=-1
- vendor/bin/phpunit
### env_file
Add environment variables from a file. Can be a single value or a list.
If you have specified a Compose file with `docker-compose -f FILE`, paths in
`env_file` are relative to the directory that file is in.
Environment variables specified in `environment` override these values.
env_file: .env
env_file:
- ./common.env
- ./apps/web.env
- /opt/secrets.env
Compose expects each line in an env file to be in `VAR=VAL` format. Lines
beginning with `#` (i.e. comments) are ignored, as are blank lines.
# Set Rails/Rack environment
RACK_ENV=development
### environment
Add environment variables. You can use either an array or a dictionary. Any
boolean values; true, false, yes no, need to be enclosed in quotes to ensure
they are not converted to True or False by the YML parser.
Environment variables with only a key are resolved to their values on the
machine Compose is running on, which can be helpful for secret or host-specific values.
environment:
RACK_ENV: development
SHOW: 'true'
SESSION_SECRET:
environment:
- RACK_ENV=development
- SHOW=true
- SESSION_SECRET
### expose
Expose ports without publishing them to the host machine - they'll only be
accessible to linked services. Only the internal port can be specified.
expose:
- "3000"
- "8000"
### extends
Extend another service, in the current file or another, optionally overriding
configuration.
You can use `extends` on any service together with other configuration keys.
The `extends` value must be a dictionary defined with a required `service`
and an optional `file` key.
extends:
file: common.yml
service: webapp
The `service` the name of the service being extended, for example
`web` or `database`. The `file` is the location of a Compose configuration
file defining that service.
If you omit the `file` Compose looks for the service configuration in the
current file. The `file` value can be an absolute or relative path. If you
specify a relative path, Compose treats it as relative to the location of the
current file.
You can extend a service that itself extends another. You can extend
indefinitely. Compose does not support circular references and `docker-compose`
returns an error if it encounters one.
For more on `extends`, see the
[the extends documentation](extends.md#extending-services).
### external_links
Link to containers started outside this `docker-compose.yml` or even outside
of Compose, especially for containers that provide shared or common services.
`external_links` follow semantics similar to `links` when specifying both the
container name and the link alias (`CONTAINER:ALIAS`).
external_links:
- redis_1
- project_db_1:mysql
- project_db_1:postgresql
### extra_hosts
Add hostname mappings. Use the same values as the docker client `--add-host` parameter.
extra_hosts:
- "somehost:162.242.195.82"
- "otherhost:50.31.209.229"
An entry with the ip address and hostname will be created in `/etc/hosts` inside containers for this service, e.g:
162.242.195.82 somehost
50.31.209.229 otherhost
### image
Tag or partial image ID. Can be local or remote - Compose will attempt to
pull if it doesn't exist locally.
image: ubuntu
image: orchardup/postgresql
image: a4bc65fd
### labels
Add metadata to containers using [Docker labels](https://docs.docker.com/engine/userguide/labels-custom-metadata/). You can use either an array or a dictionary.
It's recommended that you use reverse-DNS notation to prevent your labels from conflicting with those used by other software.
labels:
com.example.description: "Accounting webapp"
com.example.department: "Finance"
com.example.label-with-empty-value: ""
labels:
- "com.example.description=Accounting webapp"
- "com.example.department=Finance"
- "com.example.label-with-empty-value"
### links
> [Version 1 file format](#version-1) only. In version 2 files, use
> [networking](networking.md) for communication between containers.
Link to containers in another service. Either specify both the service name and
the link alias (`SERVICE:ALIAS`), or just the service name (which will also be
used for the alias).
links:
- db
- db:database
- redis
An entry with the alias' name will be created in `/etc/hosts` inside containers
for this service, e.g:
172.17.2.186 db
172.17.2.186 database
172.17.2.187 redis
Environment variables will also be created - see the [environment variable
reference](env.md) for details.
### logging
> [Version 2 file format](#version-2) only. In version 1, use
> [log_driver](#log_driver) and [log_opt](#log_opt).
Logging configuration for the service.
logging:
driver: syslog
options:
syslog-address: "tcp://192.168.0.42:123"
The `driver` name specifies a logging driver for the service's
containers, as with the ``--log-driver`` option for docker run
([documented here](https://docs.docker.com/engine/reference/logging/overview/)).
The default value is json-file.
driver: "json-file"
driver: "syslog"
driver: "none"
> **Note:** Only the `json-file` driver makes the logs available directly from
> `docker-compose up` and `docker-compose logs`. Using any other driver will not
> print any logs.
Specify logging options for the logging driver with the ``options`` key, as with the ``--log-opt`` option for `docker run`.
Logging options are key-value pairs. An example of `syslog` options:
driver: "syslog"
options:
syslog-address: "tcp://192.168.0.42:123"
### log_driver
> [Version 1 file format](#version-1) only. In version 2, use
> [logging](#logging).
Specify a log driver. The default is `json-file`.
log_driver: syslog
### log_opt
> [Version 1 file format](#version-1) only. In version 2, use
> [logging](#logging).
Specify logging options as key-value pairs. An example of `syslog` options:
log_opt:
syslog-address: "tcp://192.168.0.42:123"
### net
> [Version 1 file format](#version-1) only. In version 2, use
> [networks](#networks).
Networking mode. Use the same values as the docker client `--net` parameter.
net: "bridge"
net: "none"
net: "container:[name or id]"
net: "host"
### networks
> [Version 2 file format](#version-2) only. In version 1, use [net](#net).
Networks to join, referencing entries under the
[top-level `networks` key](#network-configuration-reference).
networks:
- some-network
- other-network
The values `bridge`, `host` and `none` can also be used, and are equivalent to
`net: "bridge"`, `net: "host"` or `net: "none"` in version 1.
There is no equivalent to `net: "container:[name or id]"`.
### pid
pid: "host"
Sets the PID mode to the host PID mode. This turns on sharing between
container and the host operating system the PID address space. Containers
launched with this flag will be able to access and manipulate other
containers in the bare-metal machine's namespace and vise-versa.
### ports
Expose ports. Either specify both ports (`HOST:CONTAINER`), or just the container
port (a random host port will be chosen).
> **Note:** When mapping ports in the `HOST:CONTAINER` format, you may experience
> erroneous results when using a container port lower than 60, because YAML will
> parse numbers in the format `xx:yy` as sexagesimal (base 60). For this reason,
> we recommend always explicitly specifying your port mappings as strings.
ports:
- "3000"
- "3000-3005"
- "8000:8000"
- "9090-9091:8080-8081"
- "49100:22"
- "127.0.0.1:8001:8001"
- "127.0.0.1:5000-5010:5000-5010"
### security_opt
Override the default labeling scheme for each container.
security_opt:
- label:user:USER
- label:role:ROLE
### ulimits
Override the default ulimits for a container. You can either specify a single
limit as an integer or soft/hard limits as a mapping.
ulimits:
nproc: 65535
nofile:
soft: 20000
hard: 40000
### volumes, volume\_driver
Mount paths or named volumes, optionally specifying a path on the host machine
(`HOST:CONTAINER`), or an access mode (`HOST:CONTAINER:ro`). Named volumes can
be specified with the
[top-level `volumes` key](#volume-configuration-reference), but this is
optional - the Docker Engine will create the volume if it doesn't exist.
You can mount a relative path on the host, which will expand relative to
the directory of the Compose configuration file being used. Relative paths
should always begin with `.` or `..`.
volumes:
# Just specify a path and let the Engine create a volume
- /var/lib/mysql
# Specify an absolute path mapping
- /opt/data:/var/lib/mysql
# Path on the host, relative to the Compose file
- ./cache:/tmp/cache
# User-relative path
- ~/configs:/etc/configs/:ro
# Named volume
- datavolume:/var/lib/mysql
If you use a volume name (instead of a volume path), you may also specify
a `volume_driver`.
volume_driver: mydriver
> Note: No path expansion will be done if you have also specified a
> `volume_driver`.
See [Docker Volumes](https://docs.docker.com/engine/userguide/dockervolumes/) and
[Volume Plugins](https://docs.docker.com/engine/extend/plugins_volume/) for more
information.
### volumes_from
Mount all of the volumes from another service or container, optionally
specifying read-only access(``ro``) or read-write(``rw``).
volumes_from:
- service_name
- service_name:ro
- container:container_name
- container:container_name:rw
> **Note:** The `container:...` formats are only supported in the
> [version 2 file format](#version-2). In [version 1](#version-1), you can use
> container names without marking them as such:
>
> - service_name
> - service_name:ro
> - container_name
> - container_name:rw
### cpu\_shares, cpu\_quota, cpuset, domainname, hostname, ipc, mac\_address, mem\_limit, memswap\_limit, privileged, read\_only, restart, stdin\_open, tty, user, working\_dir
Each of these is a single value, analogous to its
[docker run](https://docs.docker.com/engine/reference/run/) counterpart.
cpu_shares: 73
cpu_quota: 50000
cpuset: 0,1
user: postgresql
working_dir: /code
domainname: foo.com
hostname: foo
ipc: host
mac_address: 02:42:ac:11:65:43
mem_limit: 1000000000
memswap_limit: 2000000000
privileged: true
restart: always
read_only: true
stdin_open: true
tty: true
## Volume configuration reference
While it is possible to declare volumes on the fly as part of the service
declaration, this section allows you to create named volumes that can be
reused across multiple services (without relying on `volumes_from`), and are
easily retrieved and inspected using the docker command line or API.
See the [docker volume](http://docs.docker.com/reference/commandline/volume/)
subcommand documentation for more information.
### driver
Specify which volume driver should be used for this volume. Defaults to
`local`. The Docker Engine will return an error if the driver is not available.
driver: foobar
### driver_opts
Specify a list of options as key-value pairs to pass to the driver for this
volume. Those options are driver-dependent - consult the driver's
documentation for more information. Optional.
driver_opts:
foo: "bar"
baz: 1
## external
If set to `true`, specifies that this volume has been created outside of
Compose.
In the example below, instead of attemping to create a volume called
`[projectname]_data`, Compose will look for an existing volume simply
called `data` and mount it into the `db` service's containers.
version: 2
services:
db:
image: postgres
volumes:
- data:/var/lib/postgres/data
volumes:
data:
external: true
You can also specify the name of the volume separately from the name used to
refer to it within the Compose file:
volumes
data:
external:
name: actual-name-of-volume
## Network configuration reference
The top-level `networks` key lets you specify networks to be created. For a full
explanation of Compose's use of Docker networking features, see the
[Networking guide](networking.md).
### driver
Specify which driver should be used for this network.
The default driver depends on how the Docker Engine you're using is configured,
but in most instances it will be `bridge` on a single host and `overlay` on a
Swarm.
The Docker Engine will return an error if the driver is not available.
driver: overlay
### driver_opts
Specify a list of options as key-value pairs to pass to the driver for this
network. Those options are driver-dependent - consult the driver's
documentation for more information. Optional.
driver_opts:
foo: "bar"
baz: 1
### ipam
Specify custom IPAM config. This is an object with several properties, each of
which is optional:
- `driver`: Custom IPAM driver, instead of the default.
- `config`: A list with zero or more config blocks, each containing any of
the following keys:
- `subnet`: Subnet in CIDR format that represents a network segment
- `ip_range`: Range of IPs from which to allocate container IPs
- `gateway`: IPv4 or IPv6 gateway for the master subnet
- `aux_addresses`: Auxiliary IPv4 or IPv6 addresses used by Network driver,
as a mapping from hostname to IP
A full example:
ipam:
driver: default
config:
- subnet: 172.28.0.0/16
ip_range: 172.28.5.0/24
gateway: 172.28.5.254
aux_addresses:
host1: 172.28.1.5
host2: 172.28.1.6
host3: 172.28.1.7
### external
If set to `true`, specifies that this network has been created outside of
Compose.
In the example below, `proxy` is the gateway to the outside world. Instead of
attemping to create a network called `[projectname]_outside`, Compose will
look for an existing network simply called `outside` and connect the `proxy`
service's containers to it.
version: 2
services:
proxy:
build: ./proxy
networks:
- outside
- default
app:
build: ./app
networks:
- default
networks
outside:
external: true
You can also specify the name of the network separately from the name used to
refer to it within the Compose file:
networks
outside:
external:
name: actual-name-of-network
## Versioning
There are two versions of the Compose file format:
- Version 1, the legacy format. This is specified by omitting a `version` key at
the root of the YAML.
- Version 2, the recommended format. This is specified with a `version: 2` entry
at the root of the YAML.
To move your project from version 1 to 2, see the [Upgrading](#upgrading)
section.
> **Note:** If you're using
> [multiple Compose files](extends.md#different-environments) or
> [extending services](extends.md#extending-services), each file must be of the
> same version - you cannot mix version 1 and 2 in a single project.
Several things differ depending on which version you use:
- The structure and permitted configuration keys
- The minimum Docker Engine version you must be running
- Compose's behaviour with regards to networking
These differences are explained below.
### Version 1
Compose files that do not declare a version are considered "version 1". In
those files, all the [services](#service-configuration-reference) are declared
at the root of the document.
Version 1 is supported by **Compose up to 1.6.x**. It will be deprecated in a
future Compose release.
Version 1 files cannot declare named
[volumes](#volume-configuration-reference), [networks](networking.md) or
[build arguments](#args). They *can*, however, define [links](#links).
Example:
web:
build: .
ports:
- "5000:5000"
volumes:
- .:/code
links:
- redis
redis:
image: redis
### Version 2
Compose files using the version 2 syntax must indicate the version number at
the root of the document. All [services](#service-configuration-reference)
must be declared under the `services` key.
Version 2 files are supported by **Compose 1.6.0+** and require a Docker Engine
of version **1.10.0+**.
Named [volumes](#volume-configuration-reference) can be declared under the
`volumes` key, and [networks](#network-configuration-reference) can be declared
under the `networks` key.
You cannot define links when using version 2. Instead, you should use
[networking](networking.md) for communication between containers. In most cases,
this will involve less configuration than links.
Simple example:
version: 2
services:
web:
build: .
ports:
- "5000:5000"
volumes:
- .:/code
redis:
image: redis
A more extended example, defining volumes and networks:
version: 2
services:
web:
build: .
ports:
- "5000:5000"
volumes:
- .:/code
networks:
- front
- back
redis:
image: redis
volumes:
- data:/var/lib/redis
networks:
- back
volumes:
data:
driver: local
networks:
front:
driver: bridge
back:
driver: bridge
### Upgrading
In the majority of cases, moving from version 1 to 2 is a very simple process:
1. Indent the whole file by one level and put a `services:` key at the top.
2. Add a `version: 2` line at the top of the file.
3. Delete all `links` entries.
It's more complicated if you're using particular configuration features:
- `dockerfile`: This now lives under the `build` key:
build:
context: .
dockerfile: Dockerfile-alternate
- `log_driver`, `log_opt`: These now live under the `logging` key:
logging:
driver: syslog
options:
syslog-address: "tcp://192.168.0.42:123"
- `links` with aliases: If you've defined a link with an alias such as
`myservice:db`, there's currently no equivalent to this in version 2. You
will have to refer to the service using its name (in this example,
`myservice`).
- `external_links`: Links are deprecated, so you should use
[external networks](networking.md#using-externally-created-networks) to
communicate with containers outside the app.
- `net`: If you're using `host`, `bridge` or `none`, this is now replaced by
`networks`:
net: host -> networks: ["host"]
net: bridge -> networks: ["bridge"]
net: none -> networks: ["none"]
If you're using `net: "container:<name>"`, there is no equivalent to this in
version 2 - you should use [Docker networks](networking.md) for
communication instead.
## Variable substitution
Your configuration options can contain environment variables. Compose uses the
variable values from the shell environment in which `docker-compose` is run. For
example, suppose the shell contains `POSTGRES_VERSION=9.3` and you supply this
configuration:
db:
image: "postgres:${POSTGRES_VERSION}"
When you run `docker-compose up` with this configuration, Compose looks for the
`POSTGRES_VERSION` environment variable in the shell and substitutes its value
in. For this example, Compose resolves the `image` to `postgres:9.3` before
running the configuration.
If an environment variable is not set, Compose substitutes with an empty
string. In the example above, if `POSTGRES_VERSION` is not set, the value for
the `image` option is `postgres:`.
Both `$VARIABLE` and `${VARIABLE}` syntax are supported. Extended shell-style
features, such as `${VARIABLE-default}` and `${VARIABLE/foo/bar}`, are not
supported.
You can use a `$$` (double-dollar sign) when your configuration needs a literal
dollar sign. This also prevents Compose from interpolating a value, so a `$$`
allows you to refer to environment variables that you don't want processed by
Compose.
web:
build: .
command: "$$VAR_NOT_INTERPOLATED_BY_COMPOSE"
If you forget and use a single dollar sign (`$`), Compose interprets the value as an environment variable and will warn you:
The VAR_NOT_INTERPOLATED_BY_COMPOSE is not set. Substituting an empty string.
## Compose documentation
- [User guide](index.md)
- [Installing Compose](install.md)
- [Get started with Django](django.md)
- [Get started with Rails](rails.md)
- [Get started with WordPress](wordpress.md)
- [Command line reference](./reference/index.md)
Reference in New Issue View Git Blame Copy Permalink