3.5 KiB
Running Multi-Node Kubernetes Using Docker
Note: These instructions are somewhat significantly more advanced than the single node instructions. If you are interested in just starting to explore Kubernetes, we recommend that you start there.
Master Node
We'll begin by setting up the master node. For the purposes of illustration, we'll assume that the IP of this machine is MASTER_IP
Setup Docker-Bootstrap
We're going to use flannel to set up networking between Docker daemons. Flannel itself (and etcd on which it relies) will run inside of
Docker containers themselves. To achieve this, we need a separate "bootstrap" instance of the Docker daemon. This daemon will be started with
--iptables=false so that it can only run containers with --net=host. That's sufficient to bootstrap our system.
Run:
sudo docker -d -H unix:///var/run/docker-bootstrap.sock -p /var/run/docker-bootstrap.pid --iptables=false >> /var/log/docker-bootstrap.log &&
Startup etcd for flannel to use
Run:
docker -H unix:///var/run/docker-bootstrap.sock run --net=host -d kubernetes/etcd:2.0.5.1 /usr/local/bin/etcd --addr=127.0.0.1:4001 --bind-addr=0.0.0.0:4001 --data-dir=/var/etcd/data
Next,, you need to set a CIDR range for flannel. This CIDR should be chosen to be non-overlapping with any existing network you are using:
docker -H unix:///var/run/docker-bootstrap.sock run --net=host kubernetes/etcd:2.0.5.1 etcdctl set /coreos.com/network/config '{ "Network": "10.1.0.0/16" }'
Bring down Docker
To re-configure Docker to use flannel, we need to take docker down, run flannel and then restart Docker.
Turning down Docker is system dependent, it may be:
/etc/init.d/docker stop
or
systemctl stop docker
or it may be something else.
Run flannel
Now run flanneld itself:
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
The previous command should have printed a really long hash, copy this hash.
Now get the subnet settings from flannel:
docker exec <really-long-hash-from-above-here> cat /run/flannel/subnet.env
Edit the docker configuration
You now need to edit the docker configuration to activate new flags. Again, this is system specific.
This may be in /etc/docker/default or /etc/systemd/service/docker.service or it may be elsewhere.
Regardless, you need to add the following to the docker comamnd line:
--bip=${FLANNEL_SUBNET} --mtu=${FLANNEL_MTU}
Remove the existing Docker bridge
Docker creates a bridge named docker0 by default. You need to remove this:
sudo ifconfig docker0 down
sudo brctl delbr docker0
Restart Docker
Again this is system dependent, it may be:
sudo /etc/init.d/docker start
it may be:
systemctl start docker
Starting the Kubernetes Master
Ok, now that your networking is set up, you can startup Kubernetes, this is the same as the single-node case:
docker run --net=host -d -v /var/run/docker.sock:/var/run/docker.sock gcr.io/google_containers/hyperkube:v0.14.1 /hyperkube kubelet --api_servers=http://localhost:8080 --v=2 --address=0.0.0.0 --enable_server --hostname_override=127.0.0.1 --config=/etc/kubernetes/manifests
Also run the service proxy
docker run -d --net=host --privileged gcr.io/google_containers/hyperkube:v0.14.1 /hyperkube proxy --master=http://127.0.0.1:8080 --v=2