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133 lines
4.4 KiB
Markdown
133 lines
4.4 KiB
Markdown
## Adding a Kubernetes worker node via Docker.
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These instructions are very similar to the master set-up above, but they are duplicated for clarity.
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You need to repeat these instructions for each node you want to join the cluster.
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We will assume that the IP address of this node is ```${NODE_IP}``` and you have the IP address of the master in ```${MASTER_IP}``` that you created in the [master instructions](master.md).
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For each worker node, there are three steps:
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* [Set up ```flanneld``` on the worker node](#set-up-flanneld-on-the-worker-node)
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* [Start kubernetes on the worker node](#start-kubernetes-on-the-worker-node)
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* [Add the worker to the cluster](#add-the-node-to-the-cluster)
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### Set up Flanneld on the worker node
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As before, the Flannel daemon is going to provide network connectivity.
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#### Set up a bootstrap docker:
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As previously, we need a second instance of the Docker daemon running to bootstrap the flannel networking.
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Run:
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```sh
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sudo sh -c 'docker -d -H unix:///var/run/docker-bootstrap.sock -p /var/run/docker-bootstrap.pid --iptables=false --ip-masq=false --bridge=none --graph=/var/lib/docker-bootstrap 2> /var/log/docker-bootstrap.log 1> /dev/null &'
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```
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_Important Note_:
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If you are running this on a long running system, rather than experimenting, you should run the bootstrap Docker instance under something like SysV init, upstart or systemd so that it is restarted
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across reboots and failures.
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#### Bring down Docker
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To re-configure Docker to use flannel, we need to take docker down, run flannel and then restart Docker.
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Turning down Docker is system dependent, it may be:
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```sh
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sudo /etc/init.d/docker stop
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```
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or
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```sh
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sudo systemctl stop docker
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```
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or it may be something else.
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#### Run flannel
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Now run flanneld itself, this call is slightly different from the above, since we point it at the etcd instance on the master.
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```sh
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sudo docker -H unix:///var/run/docker-bootstrap.sock run -d --net=host --privileged -v /dev/net:/dev/net quay.io/coreos/flannel:0.3.0 /opt/bin/flanneld --etcd-endpoints=http://${MASTER_IP}:4001
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```
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The previous command should have printed a really long hash, copy this hash.
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Now get the subnet settings from flannel:
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```
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sudo docker -H unix:///var/run/docker-bootstrap.sock exec <really-long-hash-from-above-here> cat /run/flannel/subnet.env
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```
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#### Edit the docker configuration
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You now need to edit the docker configuration to activate new flags. Again, this is system specific.
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This may be in ```/etc/default/docker``` or ```/etc/systemd/service/docker.service``` or it may be elsewhere.
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Regardless, you need to add the following to the docker comamnd line:
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```sh
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--bip=${FLANNEL_SUBNET} --mtu=${FLANNEL_MTU}
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```
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#### Remove the existing Docker bridge
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Docker creates a bridge named ```docker0``` by default. You need to remove this:
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```sh
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sudo /sbin/ifconfig docker0 down
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sudo brctl delbr docker0
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```
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You may need to install the ```bridge-utils``` package for the ```brctl``` binary.
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#### Restart Docker
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Again this is system dependent, it may be:
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```sh
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sudo /etc/init.d/docker start
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```
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it may be:
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```sh
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systemctl start docker
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```
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### Start Kubernetes on the worker node
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#### Run the kubelet
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Again this is similar to the above, but the ```--api_servers``` now points to the master we set up in the beginning.
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```sh
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sudo docker run --net=host -d -v /var/run/docker.sock:/var/run/docker.sock gcr.io/google_containers/hyperkube:v0.14.2 /hyperkube kubelet --api_servers=http://${MASTER_IP}:8080 --v=2 --address=0.0.0.0 --enable_server --hostname_override=$(hostname -i)
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```
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#### Run the service proxy
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The service proxy provides load-balancing between groups of containers defined by Kubernetes ```Services```
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```sh
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sudo docker run -d --net=host --privileged gcr.io/google_containers/hyperkube:v0.14.2 /hyperkube proxy --master=http://${MASTER_IP}:8080 --v=2
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```
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### Add the node to the cluster
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On the master you created above, create a file named ```node.yaml``` make it's contents:
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```yaml
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apiVersion: v1beta1
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externalID: ${NODE_IP}
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hostIP: ${NODE_IP}
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id: ${NODE_IP}
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kind: Node
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resources:
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capacity:
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# Adjust these to match your node
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cpu: "1"
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memory: 3892043776
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```
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Make the API call to add the node, you should do this on the master node that you created above. Otherwise you need to add ```-s=http://${MASTER_IP}:8080``` to point ```kubectl``` at the master.
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```sh
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./kubectl create -f node.yaml
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```
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### Next steps
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Move on to [testing your cluster](testing.md) or [add another node](#adding-a-kubernetes-worker-node-via-docker)
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