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a0ccd0d42f
There are currently problems with "swarm init" and "swarm join" when an explicit --listen-addr flag is not provided. swarmkit defaults to finding the IP address associated with the default route, and in cloud setups this is often the wrong choice. Introduce a notion of "advertised address", with the client flag --advertise-addr, and the daemon flag --swarm-default-advertise-addr to provide a default. The default listening address is now 0.0.0.0, but a valid advertised address must be detected or specified. If no explicit advertised address is specified, error out if there is more than one usable candidate IP address on the system. This requires a user to explicitly choose instead of letting swarmkit make the wrong choice. For the purposes of this autodetection, we ignore certain interfaces that are unlikely to be relevant (currently docker*). The user is also required to choose a listen address on swarm init if they specify an explicit advertise address that is a hostname or an IP address that's not local to the system. This is a requirement for overlay networking. Also support specifying interface names to --listen-addr, --advertise-addr, and the daemon flag --swarm-default-advertise-addr. This will fail if the interface has multiple IP addresses (unless it has a single IPv4 address and a single IPv6 address - then we resolve the tie in favor of IPv4). This change also exposes the node's externally-reachable address in docker info, as requested by #24017. Make corresponding API and CLI docs changes. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
92 lines
2.6 KiB
Markdown
92 lines
2.6 KiB
Markdown
<!--[metadata]>
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+++
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title = "Create a swarm"
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description = "Initialize the swarm"
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keywords = ["tutorial, cluster management, swarm mode"]
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advisory = "rc"
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[menu.main]
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identifier="initialize-swarm"
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parent="swarm-tutorial"
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weight=12
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+++
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<![end-metadata]-->
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# Create a swarm
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After you complete the [tutorial setup](index.md) steps, you're ready
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to create a swarm. Make sure the Docker Engine daemon is started on the host
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machines.
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1. Open a terminal and ssh into the machine where you want to run your manager
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node. For example, the tutorial uses a machine named `manager1`.
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2. Run the following command to create a new swarm:
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```bash
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docker swarm init --advertise-addr <MANAGER-IP>
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```
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In the tutorial, the following command creates a swarm on the `manager1`
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machine:
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```bash
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$ docker swarm init --advertise-addr 192.168.99.100
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Swarm initialized: current node (dxn1zf6l61qsb1josjja83ngz) is now a manager.
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To add a worker to this swarm, run the following command:
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docker swarm join \
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--token SWMTKN-1-49nj1cmql0jkz5s954yi3oex3nedyz0fb0xx14ie39trti4wxv-8vxv8rssmk743ojnwacrr2e7c \
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192.168.99.100:2377
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To add a manager to this swarm, run the following command:
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docker swarm join \
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--token SWMTKN-1-61ztec5kyafptydic6jfc1i33t37flcl4nuipzcusor96k7kby-5vy9t8u35tuqm7vh67lrz9xp6 \
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192.168.99.100:2377
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```
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The `--advertise-addr` flag configures the manager node to publish its
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address as `192.168.99.100`. The other nodes in the swarm must be able
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to access the manager at the IP address.
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The output incudes the commands to join new nodes to the swarm. Nodes will
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join as managers or workers depending on the value for the `--swarm-token`
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flag.
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2. Run `docker info` to view the current state of the swarm:
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```bash
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$ docker info
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Containers: 2
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Running: 0
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Paused: 0
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Stopped: 2
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...snip...
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Swarm: active
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NodeID: dxn1zf6l61qsb1josjja83ngz
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Is Manager: true
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Managers: 1
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Nodes: 1
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...snip...
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```
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3. Run the `docker node ls` command to view information about nodes:
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```bash
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$ docker node ls
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ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
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dxn1zf6l61qsb1josjja83ngz * manager1 Ready Active Leader
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```
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The `*` next to the node id indicates that you're currently connected on
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this node.
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Docker Engine swarm mode automatically names the node for the machine host
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name. The tutorial covers other columns in later steps.
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## What's next?
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In the next section of the tutorial, we'll [add two more nodes](add-nodes.md) to
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the cluster.
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