虚拟机：VMware® Workstation 12 Pro
系统：CentOS Linux release 7.2.1511 (Core) 3.10.0-327.el7.x86_64
由于刚开始学习k8s，本次软件的安装，我们都采用最简单的方式，能用yum 安装的尽量采用yum安装
1、ETCD安装
ETCD官方文档：https://github.com/coreos/etcd/blob/master/Documentation/docs.md
1.1 检查ETCD版本
[root@localhost ~]# yum list|grep etcd
etcd.x86_64 2.3.7-4.el7 @extras
[root@localhost ~]#
1.2 安装ETCD
yum install etcd
1.3 修改ETCD配置
安装好后，系统会自动生成etcd.service文件（路径为/usr/lib/systemd/system/），修改对应的配置
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target
[Service]
Type=notify
WorkingDirectory=/var/lib/etcd/
EnvironmentFile=-/etc/etcd/etcd.conf
User=etcd
# set GOMAXPROCS to number of processors
ExecStart=/bin/bash -c "GOMAXPROCS=$(nproc) /usr/bin/etcd \
--name=\"${ETCD_NAME}\" \
--data-dir=\"${ETCD_DATA_DIR}\" \
--listen-peer-urls=\"${ETCD_LISTEN_PEER_URLS}\" \
--advertise-client-urls=\"${ETCD_ADVERTISE_CLIENT_URLS}\" \
--initial-cluster-token=\"${ETCD_INITIAL_CLUSTER_TOKEN}\" \
--initial-cluster=\"${ETCD_INITIAL_CLUSTER}\" \
--initial-cluster-state=\"${ETCD_INITIAL_CLUSTER_STATE}\" \
--listen-client-urls=\"${ETCD_LISTEN_CLIENT_URLS}\""
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
并配置其配置文件
ETCD_NAME=zwetcd_2
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"ETCD_LISTEN_PEER_URLS="http://192.168.37.131:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.37.131:2379,http://127.0.0.1:2379"
#[cluster]
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.37.131:2380"
# if you use different ETCD_NAME (e.g. test), set ETCD_INITIAL_CLUSTER value for this name, i.e. "test=http://..."
ETCD_INITIAL_CLUSTER="zwetcd_2=http://192.168.37.131:2380,zwetcd_1=http://192.168.37.130:2380"
ETCD_INITIAL_CLUSTER_STATE="new"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_ADVERTISE_CLIENT_URLS="http://192.168.37.131:2379"
如果使用firewalld作为防火墙，则需要开放端口：
firewall-cmd --zone=public --add-port=2379/tcp --permanent
firewall-cmd --zone=public --add-port=2380/tcp --permanent
firewall-cmd --reload
firewall-cmd --list-all
问题：
1、本地连接报错
[root@localhost system]# etcdctl ls /
Error: client: etcd cluster is unavailable or misconfigured
error #0: dial tcp 127.0.0.1:2379: getsockopt: connection refused
error #1: dial tcp 127.0.0.1:4001: getsockopt: connection refused
如果出现如上的错误，是因为ETCD_LISTEN_CLIENT_URLS参数没有配置http://127.0.0.1:2379而导致的，不过已经配置了具体的IP，还需要配置本地链路，这个就有点奇怪了。
2、Docker安装
2.1、检查docker版本
yum list |grep docker
[root@localhost ~]# yum list|grep docker
docker.x86_64 1.10.3-46.el7.centos.14 @extras
docker-common.x86_64 1.10.3-46.el7.centos.14 @extras
docker-selinux.x86_64 1.10.3-46.el7.centos.14 @extras
cockpit-docker.x86_64 0.114-2.el7.centos extras
docker-devel.x86_64 1.3.2-4.el7.centos extras
docker-distribution.x86_64 2.4.1-2.el7 extras
docker-forward-journald.x86_64 1.10.3-44.el7.centos extras
docker-latest.x86_64 1.12.1-2.el7.centos extras
docker-latest-logrotate.x86_64 1.12.1-2.el7.centos extras
docker-latest-v1.10-migrator.x86_64 1.12.1-2.el7.centos extras
docker-logrotate.x86_64 1.10.3-46.el7.centos.14 extras
docker-lvm-plugin.x86_64 1.10.3-46.el7.centos.14 extras
docker-novolume-plugin.x86_64 1.10.3-46.el7.centos.14 extras
docker-python.x86_64 1.4.0-115.el7 extras
docker-registry.noarch 0.6.8-8.el7 extras
docker-registry.x86_64 0.9.1-7.el7 extras
docker-unit-test.x86_64 1.10.3-46.el7.centos.14 extras
docker-v1.10-migrator.x86_64 1.10.3-46.el7.centos.14 extras
python-docker-py.noarch 1.7.2-1.el7 extras
[root@localhost ~]#
2.2 安装docker
1 yum install docker -y
2.3 检查docker安装信息
[root@localhost ~]# docker version
Client:
Version: 1.10.3
API version: 1.22
Package version: docker-common-1.10.3-46.el7.centos.14.x86_64
Go version: go1.6.3
Git commit: cb079f6-unsupported
Built: Fri Sep 16 13:24:25 2016
OS/Arch: linux/amd64
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
3 flannel
3.1 检查flannel版本
[root@localhost etcd]# yum list |grep flannel
flannel.x86_64 0.5.3-9.el7 @extras
3.2 安装flannel
yum install flannel
3.3 修改service配置
查看flannel的配置文件（使用yum安装会自动生成此文件，如果下载的执行文件则需要手动生成，在使用systemctl命令执行service 的时候会用到），可以看到flannel的service配置如下：
[root@localhost etcd]# more /usr/lib/systemd/system/flanneld.service
[Unit]
Description=Flanneld overlay address etcd agent
After=network.target
After=network-online.target
Wants=network-online.target
After=etcd.service
Before=docker.service
[Service]
Type=notify
EnvironmentFile=/etc/sysconfig/flanneld
EnvironmentFile=-/etc/sysconfig/docker-network
ExecStart=/usr/bin/flanneld -etcd-endpoints=${FLANNEL_ETCD} -etcd-prefix=${FLANNEL_ETCD_KEY} $FLANNEL_OPTIONS
ExecStartPost=/usr/libexec/flannel/mk-docker-opts.sh -k DOCKER_NETWORK_OPTIONS -d /run/flannel/docker
Restart=on-failure
[Install]
WantedBy=multi-user.target
RequiredBy=docker.service
其中所有的参数都配置在/etc/sysconfig/flanneld文件中，修改此文件，初始文件如下：
# Flanneld configuration options
# etcd url location. Point this to the server where etcd runs
FLANNEL_ETCD="http://127.0.0.1:2379"
# etcd config key. This is the configuration key that flannel queries
# For address range assignment
FLANNEL_ETCD_KEY="/atomic.io/network"
# Any additional options that you want to pass
FLANNEL_OPTIONS=""
其中
FLANNEL_ETCD：为ETCD的地址，
FLANNEL_ETCD_KEY：为在etcd中配置的网络参数的key
FLANNEL_OPTIONS：为flannel的启动参数，我在这里加上了监听的网卡
根据前面步骤中etcd的配置，我们修改配置文件如下：
# Flanneld configuration options
# etcd url location. Point this to the server where etcd runs
FLANNEL_ETCD="http://192.168.37.130:2379"
# etcd config key. This is the configuration key that flannel queries
# For address range assignment
FLANNEL_ETCD_KEY="/flannel/network"
# Any additional options that you want to pass
FLANNEL_OPTIONS="--iface=eno16777736"
3.4 启动FLANNEL
可以使用service flanneld start 或者systemctl start flannel启动flannel
3.5 修改docker网络
因为docker需要使用flanneld的网络，因此需要修改docker的service文件：
[Unit]
Description=Docker Application Container Engine
Documentation=http://docs.docker.com
After=network.target rhel-push-plugin.socket
Wants=docker-storage-setup.service
[Service]
Type=notify
NotifyAccess=all
#import flannel configuration
EnvironmentFile=-/etc/sysconfig/flanneld
EnvironmentFile=-/run/flannel/subnet.env
EnvironmentFile=-/etc/sysconfig/docker
EnvironmentFile=-/etc/sysconfig/docker-storage
EnvironmentFile=-/etc/sysconfig/docker-network
Environment=GOTRACEBACK=crash
ExecStart=/usr/bin/docker-current daemon \
--exec-opt native.cgroupdriver=systemd \
$OPTIONS \
$DOCKER_STORAGE_OPTIONS \
$DOCKER_NETWORK_OPTIONS \
$ADD_REGISTRY \
$BLOCK_REGISTRY \
$INSECURE_REGISTRY \
--bip=${FLANNEL_SUBNET}
LimitNOFILE=1048576
LimitNPROC=1048576
LimitCORE=infinity
TimeoutStartSec=0
MountFlags=slave
Restart=on-abnormal
[Install]
WantedBy=multi-user.target
在执行前增加配置文件
EnvironmentFile=-/etc/sysconfig/flanneld
EnvironmentFile=-/run/flannel/subnet.env
执行命令增加参数 --bip=${FLANNEL_SUBNET}
重启docker
systemctl daemon-reload
systemctl restart docker
3.6 问题
1、Failed to retrieve network config: 104: Not a directory (/flannel/network/config)
问题原因：在初次配置的时候，把flannel的配置文件中的etcd-prefix-key配置成了/flannel/network/config，实际上应该是/flannel/network
注意：如上配置需要在集群的所有机器上执行，完成后，上述安装的各个系统的启动顺序应该是：
systemctl start etcd
systemctl start flannel
systemctl start docker
配置完检查：
使用ip a检查当前的网络的准备情况：
[root@localhost system]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:79:cf:e3 brd ff:ff:ff:ff:ff:ff
inet 192.168.37.130/24 brd 192.168.37.255 scope global dynamic eno16777736
valid_lft 1554sec preferred_lft 1554sec
inet6 fe80::20c:29ff:fe79:cfe3/64 scope link
valid_lft forever preferred_lft forever
9: flannel0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1472 qdisc pfifo_fast state UNKNOWN qlen 500
link/none
inet 172.17.75.0/16 scope global flannel0
valid_lft forever preferred_lft forever
10: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN
link/ether 02:42:e3:f0:0d:05 brd ff:ff:ff:ff:ff:ff
inet 172.17.75.1/24 scope global docker0
valid_lft forever preferred_lft forever
如果看到到flannel0余docker0的网段相同，则网络配置成功。