# Kubernetes deployed on multiple ubuntu nodes This document describes how to deploy kubernetes on multiple ubuntu nodes, including 1 master node and 3 minion nodes, and people uses this approach can scale to **any number of minion nodes** by changing some settings with ease. Although there exists saltstack based ubuntu k8s installation , it may be tedious and hard for a guy that knows little about saltstack but want to build a really distributed k8s cluster. This approach is inspired by [k8s deploy on a single node](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/getting-started-guides/ubuntu_single_node.md). [Cloud team from ZJU](https://github.com/ZJU-SEL) will keep updating this work. ### **Prerequisites：** *1 The minion nodes have installed docker version 1.2+* *2 All machines can communicate with each orther, no need to connect Internet (should use private docker registry in this case)* *3 These guide is tested OK on Ubuntu 14.04 LTS 64bit server, but it should also work on most Ubuntu versions* *4 Dependences of this guide: etcd-2.0.0, flannel-0.2.0, k8s-0.12.0, but it may work with higher versions* ### **Main Steps** #### I. Make *kubernetes* , *etcd* and *flanneld* binaries On your laptop, copy `cluster/ubuntu-cluster` directory to your workspace. The `build.sh` will download and build all the needed binaries into `./binaries`. You can customize your etcd version or K8s version in the build.sh by changing variable `ETCD_V` and `K8S_V` in build.sh, default etcd version is 2.0.0 and K8s version is 0.12.0. ``` $ cd cluster/ubuntu-cluster $ sudo ./build.sh ``` Please copy all the files in `./binaries` into `/opt/bin` of every machine you want to run as Kubernetes cluster node. Alternatively, if your Kubernetes nodes have access to Internet, you can copy `cluster/ubuntu-cluster` directory to every node and run: ``` # in every node $ cd cluster/ubuntu-cluster $ sudo ./build.sh $ sudo cp ./binaries/* /opt/bin ``` > We used flannel here because we want to use overlay network, but please remember it is not the only choice, and it is also not a k8s' necessary dependence. Actually you can just build up k8s cluster natively, or use flannel, Open vSwitch or any other SDN tool you like, we just choose flannel here as a example. #### II. Configue and install every components upstart script An example cluster is listed as below: | IP Address|Role | |---------|------| |10.10.103.223| minion| |10.10.103.224| minion| |10.10.103.162| minion| |10.10.103.250| master| First of all, make sure `cluster/ubuntu-cluster` exists on this node，and run `configue.sh`. On master( infra1 10.10.103.250 ) node: ``` # in cluster/ubuntu-cluster $ sudo ./configure.sh Welcome to use this script to configure k8s setup Please enter all your cluster node ips, MASTER node comes first And separated with blank space like " ": 10.10.103.250 10.10.103.223 10.10.103.224 10.10.103.162 This machine acts as both MASTER and MINION: 1 only MASTER: 2 only MINION: 3 Please choose a role > 2 IP address of this machine > 10.10.103.250 Configure Success ``` On every minion ( e.g. 10.10.103.224 ) node: ``` # in cluster/ubuntu-cluster $ sudo ./configure.sh Welcome to use this script to configure k8s setup Please enter all your cluster node ips, MASTER node comes first And separated with blank space like " ": 10.10.103.250 10.10.103.223 10.10.103.224 10.10.103.162 This machine acts as both MASTER and MINION: 1 only MASTER: 2 only MINION: 3 Please choose a role > 3 IP address of this machine > 10.10.103.224 Configure Success ``` If you want a node acts as **both running the master and minion**, please choose option 1. #### III. Start all components 1. On the master node: `$ sudo service etcd start` Then on every minion node: `$ sudo service etcd start` > The kubernetes commands will be started automatically after etcd 2. On any node: `$ /opt/bin/etcdctl mk /coreos.com/network/config '{"Network":"10.0.0.0/16"}'` > You can use the below command on another node to comfirm if the network setting is correct. > `$ /opt/bin/etcdctl get /coreos.com/network/config` > If you got `{"Network":"10.0.0.0/16"}`, then etcd cluster is working well. > If not , please check` /var/log/upstart/etcd.log` to resolve etcd problem before going forward. > Finally, use `ifconfig` to see if there is a new network interface named `flannel0` coming up. 3. On every minion node Make sure you have `brctl` installed on every minion, otherwise please run `sudo apt-get install bridge-utils` `$ sudo ./reconfigureDocker.sh` This will make the docker daemon aware of flannel network. **All done !** #### IV. Validation You can use kubectl command to see if the newly created k8s is working correctly. For example , `$ kubectl get minions` to see if you get all your minion nodes comming up. Also you can run kubernetes [guest-example](https://github.com/GoogleCloudPlatform/kubernetes/tree/master/examples/guestbook) to build a redis backend cluster on the k8s． #### V. Trouble Shooting Generally, what of this guide did is quite simple: 1. Build and copy binaries and configuration files to proper dirctories on every node 2. Configure `etcd` using IPs based on input from user 3. Create and start flannel network So, whenver you have problem, do not blame Kubernetes, **check etcd configuration first** Please try: 1. Check `/var/log/upstart/etcd.log` for suspicisous etcd log 2. Check `/etc/default/etcd`, as we do not have much input validation, a right config should be like: ``` ETCD_OPTS="-name infra1 -initial-advertise-peer-urls -listen-peer-urls -initial-cluster-token etcd-cluster-1 -initial-cluster infra1=,infra2=,infra3= -initial-cluster-state new" ``` 3. Remove `data-dir` of etcd and run `reconfigureDocker.sh`again, the default path of `data-dir` is /infra*.etcd/ 4. You can also customize your own settings in `/etc/default/{component_name}` after configured success.