Merge pull request #4260 from dvdksn/docs/host-flag

docs: add description and examples for docker -H
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Sebastiaan van Stijn 2023-05-08 14:06:35 +02:00 committed by GitHub
commit 03752a6ba6
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2 changed files with 63 additions and 13 deletions

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@ -83,7 +83,7 @@ func (o *ClientOptions) InstallFlags(flags *pflag.FlagSet) {
// opts.ValidateHost is not used here, so as to allow connection helpers
hostOpt := opts.NewNamedListOptsRef("hosts", &o.Hosts, nil)
flags.VarP(hostOpt, "host", "H", "Daemon socket(s) to connect to")
flags.VarP(hostOpt, "host", "H", "Daemon socket to connect to")
flags.StringVarP(&o.Context, "context", "c", "",
`Name of the context to use to connect to the daemon (overrides `+client.EnvOverrideHost+` env var and default context set with "docker context use")`)
}

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@ -92,18 +92,18 @@ The base command for the Docker CLI.
### Options
| Name | Type | Default | Description |
|:--------------------|:---------|:-------------------------|:--------------------------------------------------------------------------------------------------------------------------------------|
| `--config` | `string` | `/root/.docker` | Location of client config files |
| `-c`, `--context` | `string` | | Name of the context to use to connect to the daemon (overrides DOCKER_HOST env var and default context set with `docker context use`) |
| `-D`, `--debug` | | | Enable debug mode |
| `-H`, `--host` | `list` | | Daemon socket(s) to connect to |
| `-l`, `--log-level` | `string` | `info` | Set the logging level (`debug`, `info`, `warn`, `error`, `fatal`) |
| `--tls` | | | Use TLS; implied by --tlsverify |
| `--tlscacert` | `string` | `/root/.docker/ca.pem` | Trust certs signed only by this CA |
| `--tlscert` | `string` | `/root/.docker/cert.pem` | Path to TLS certificate file |
| `--tlskey` | `string` | `/root/.docker/key.pem` | Path to TLS key file |
| `--tlsverify` | | | Use TLS and verify the remote |
| Name | Type | Default | Description |
|:---------------------------------|:---------|:-------------------------|:--------------------------------------------------------------------------------------------------------------------------------------|
| `--config` | `string` | `/root/.docker` | Location of client config files |
| `-c`, `--context` | `string` | | Name of the context to use to connect to the daemon (overrides DOCKER_HOST env var and default context set with `docker context use`) |
| `-D`, `--debug` | | | Enable debug mode |
| [`-H`](#host), [`--host`](#host) | `list` | | Daemon socket to connect to |
| `-l`, `--log-level` | `string` | `info` | Set the logging level (`debug`, `info`, `warn`, `error`, `fatal`) |
| `--tls` | | | Use TLS; implied by --tlsverify |
| `--tlscacert` | `string` | `/root/.docker/ca.pem` | Trust certs signed only by this CA |
| `--tlscert` | `string` | `/root/.docker/cert.pem` | Path to TLS certificate file |
| `--tlskey` | `string` | `/root/.docker/key.pem` | Path to TLS key file |
| `--tlsverify` | | | Use TLS and verify the remote |
<!---MARKER_GEN_END-->
@ -378,6 +378,56 @@ list of root Certificate Authorities.
## Examples
### <a name="host"></a> Specify daemon host (-H, --host)
You can use the `-H`, `--host` flag to specify a socket to use when you invoke
a `docker` command. You can use the following protocols:
| Scheme | Description | Example |
|----------------------------------------|---------------------------|----------------------------------|
| `unix://[<path>]` | Unix socket (Linux only) | `unix:///var/run/docker.sock` |
| `tcp://[<IP or host>[:port]]` | TCP connection | `tcp://174.17.0.1:2376` |
| `ssh://[username@]<IP or host>[:port]` | SSH connection | `ssh://user@192.168.64.5` |
| `npipe://[<name>]` | Named pipe (Windows only) | `npipe:////./pipe/docker_engine` |
If you don't specify the `-H` flag, and you're not using a custom
[context](https://docs.docker.com/engine/context/working-with-contexts),
commands use the following default sockets:
- `unix:///var/run/docker.sock` on macOS and Linux
- `npipe:////./pipe/docker_engine` on Windows
To achieve a similar effect without having to specify the `-H` flag for every
command, you could also [create a context](context_create.md),
or alternatively, use the
[`DOCKER_HOST` environment variable](#environment-variables).
For more information about the `-H` flag, see
[Daemon socket option](dockerd.md#daemon-socket-option).
#### Using TCP sockets
The following example shows how to invoke `docker ps` over TCP, to a remote
daemon with IP address `174.17.0.1`, listening on port `2376`:
```console
$ docker -H tcp://174.17.0.1:2376 ps
```
> **Note**
>
> By convention, the Docker daemon uses port `2376` for secure TLS connections,
> and port `2375` for insecure, non-TLS connections.
#### Using SSH sockets
When you use SSH invoke a command on a remote daemon, the request gets forwarded
to the `/var/run/docker.sock` Unix socket on the SSH host.
```console
$ docker -H ssh://user@192.168.64.5 ps
```
### Display help text
To list the help on any command just execute the command, followed by the