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018282f392
This was discussed and agreed in #246. It will probably break a few outstanding PRs as well as a few external links but it's for the better good long term.
82 lines
2.1 KiB
Markdown
82 lines
2.1 KiB
Markdown
# Managing hosts with Docker Machine
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- Docker Machine is a tool to provision and manage Docker hosts.
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- It automates the creation of a virtual machine:
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- locally, with a tool like VirtualBox or VMware;
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- on a public cloud like AWS EC2, Azure, Digital Ocean, GCP, etc.;
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- on a private cloud like OpenStack.
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- It can also configure existing machines through an SSH connection.
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- It can manage as many hosts as you want, with as many "drivers" as you want.
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---
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## Docker Machine workflow
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1) Prepare the environment: setup VirtualBox, obtain cloud credentials ...
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2) Create hosts with `docker-machine create -d drivername machinename`.
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3) Use a specific machine with `eval $(docker-machine env machinename)`.
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4) Profit!
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---
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## Environment variables
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- Most of the tools (CLI, libraries...) connecting to the Docker API can use environment variables.
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- These variables are:
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- `DOCKER_HOST` (indicates address+port to connect to, or path of UNIX socket)
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- `DOCKER_TLS_VERIFY` (indicates that TLS mutual auth should be used)
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- `DOCKER_CERT_PATH` (path to the keypair and certificate to use for auth)
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- `docker-machine env ...` will generate the variables needed to connect to a host.
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- `$(eval docker-machine env ...)` sets these variables in the current shell.
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---
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## Host management features
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With `docker-machine`, we can:
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- upgrade a host to the latest version of the Docker Engine,
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- start/stop/restart hosts,
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- get a shell on a remote machine (with SSH),
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- copy files to/from remotes machines (with SCP),
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- mount a remote host's directory on the local machine (with SSHFS),
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- ...
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---
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## The `generic` driver
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When provisioning a new host, `docker-machine` executes these steps:
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1) Create the host using a cloud or hypervisor API.
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2) Connect to the host over SSH.
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3) Install and configure Docker on the host.
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With the `generic` driver, we provide the IP address of an existing host
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(instead of e.g. cloud credentials) and we omit the first step.
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This allows to provision physical machines, or VMs provided by a 3rd
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party, or use a cloud for which we don't have a provisioning API.
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