Learning KVM - part3 配置KVM存储共享池

上一章节我们安装了KVM和KVM管理工具，接下来我们配置KVM宿主机（hosts）为虚拟机（guests）提供网络以及存储资源。
KVM安装完成后默认会虚拟机（guests）创建文件系统/var/lib/libvirt/images，如果您打算在宿主机（hosts）之间迁移VM（guests）的话，你需要配置共享存储，例如NFS、NAS或Ceph等。
同时你必须配置网桥，以便VM能够与外部通讯。接下来我们将描述如何配置网桥以及如何为VM及镜像创建存储资源池。

如何配置网桥

如果您发现您的机器上有"virbr0"网卡，您可以使用命令virsh net-destroy default去删除它或者选择忽略，这个网卡是KVM安装时自动创建的NAT网卡。
下面我们来手动配置网桥桥接到网卡"eth1",步骤如下：

1. 登录到宿主机，检查网络配置；

   [root@localhost ~]# ip a
   1: lo:  mtu 65536 qdisc noqueue state UNKNOWN qlen 1
       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: eth0:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
       link/ether 00:0c:29:f5:9f:b2 brd ff:ff:ff:ff:ff:ff
       inet 192.168.88.144/24 brd 192.168.88.255 scope global dynamic eth0
          valid_lft 1248sec preferred_lft 1248sec
       inet6 fe80::ec2f:eb00:c9f6:4250/64 scope link
          valid_lft forever preferred_lft forever
   3: eth1:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
       link/ether 00:0c:29:f5:9f:bc brd ff:ff:ff:ff:ff:ff
       inet 192.168.57.254/24 brd 192.168.57.255 scope global eth1
          valid_lft forever preferred_lft forever
       inet6 fe80::e096:d49b:5afe:d1ca/64 scope link
          valid_lft forever preferred_lft forever
   

2. 配置网卡"eth1"桥接网桥；

   [root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth1
   [root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
   TYPE=Ethernet
   BOOTPROTO=static
   IPV4_FAILURE_FATAL=no
   NAME=eth1
   DEVICE=eth1
   ONBOOT=yes
   BRIDGE=br0
   

3. 创建网桥"br0"的配置文件；

   [root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-br0
   [root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-br0
   TYPE="Bridge"
   DEVICE=br0
   BOOTPROTO=static
   IPADDR=192.168.57.254
   NETMASK=255.255.255.0
   ONBOOT="yes"
   DELAY=0
   STP=0
   

4. 开启ipv4路由转发功能；

   [root@localhost ~]# grep "net.ipv4.ip_forward" /etc/sysctl.conf || echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf
   [root@localhost ~]# sysctl -p
   net.ipv4.ip_forward = 1
   

5. 重启网络服使网桥"br0"配置生效；

   [root@localhost ~]# systemctl network restart
   Unknown operation 'network'.
   [root@localhost ~]# systemctl restart network
   [root@localhost ~]# systemctl status network
   ● network.service - LSB: Bring up/down networking
      Loaded: loaded (/etc/rc.d/init.d/network; bad; vendor preset: disabled)
      Active: active (exited) since Thu 2017-06-08 14:37:50 CST; 6s ago
        Docs: man:systemd-sysv-generator(8)
     Process: 6568 ExecStop=/etc/rc.d/init.d/network stop (code=exited, status=0/SUCCESS)
     Process: 6793 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=0/SUCCESS)
   
   Jun 08 14:37:49 localhost.localdomain systemd[1]: Starting LSB: Bring up/down networking...
   Jun 08 14:37:49 localhost.localdomain network[6793]: Bringing up loopback interface:  [  OK  ]
   Jun 08 14:37:50 localhost.localdomain network[6793]: Bringing up interface eth0:  Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/3)
   Jun 08 14:37:50 localhost.localdomain network[6793]: [  OK  ]
   Jun 08 14:37:50 localhost.localdomain network[6793]: Bringing up interface eth1:  Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/4)
   Jun 08 14:37:50 localhost.localdomain network[6793]: [  OK  ]
   Jun 08 14:37:50 localhost.localdomain network[6793]: Bringing up interface br0:  [  OK  ]
   Jun 08 14:37:50 localhost.localdomain systemd[1]: Started LSB: Bring up/down networking.
   [root@localhost ~]# ip a
   1: lo:  mtu 65536 qdisc noqueue state UNKNOWN qlen 1
       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: eth0:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
       link/ether 00:0c:29:f5:9f:b2 brd ff:ff:ff:ff:ff:ff
       inet 192.168.88.144/24 brd 192.168.88.255 scope global dynamic eth0
          valid_lft 1786sec preferred_lft 1786sec
       inet6 fe80::ec2f:eb00:c9f6:4250/64 scope link
          valid_lft forever preferred_lft forever
   3: eth1:  mtu 1500 qdisc pfifo_fast master br0 state UP qlen 1000
       link/ether 00:0c:29:f5:9f:bc brd ff:ff:ff:ff:ff:ff
   4: br0:  mtu 1500 qdisc noqueue state UP qlen 1000
       link/ether 00:0c:29:f5:9f:bc brd ff:ff:ff:ff:ff:ff
       inet 192.168.57.254/24 brd 192.168.57.255 scope global br0
          valid_lft forever preferred_lft forever
       inet6 fe80::20c:29ff:fef5:9fbc/64 scope link
          valid_lft forever preferred_lft forever
   

6. 检查网桥信息,看上去“br0”已经桥接到“eth1”了；

   [root@localhost ~]# brctl show
   bridge name bridge id       STP enabled interfaces
   br0     8000.000c29f59fbc   no      eth1
   

---

配置存储资源池

KVM默认的存储资源池的路径为/var/lib/libvirt/images。
用户没有强要求使用共享存储来存储镜像（images），配置共享存储能够很方便实现在宿主机之间迁移vm的功能，KVM已经支持vm热迁移功能，这点类似于VMware的vmotion功能。
KVM支持多种共享存储做为存储资源池。
本章我们使用NFS，首先我们来搭建一个NFS环境。

NFS环境搭搭建

# 安装nfs rpm包
[root@nfs-server ~]# yum install -y nfs-utils
# 配置共享目录，允许本网段访问
[root@nfs-server ~]# mkdir /images
[root@nfs-server ~]# echo -e "/images\t192.168.57.0/24(rw,no_root_squash)" > /etc/exports
# 启动NFS服务
[root@nfs-server ~]# systemctl enable rpcbind nfs-server
Created symlink from /etc/systemd/system/multi-user.target.wants/nfs-server.service to /usr/lib/systemd/system/nfs-server.service.
[root@nfs-server ~]# systemctl start rpcbind nfs-server
[root@nfs-server ~]# systemctl status rpcbind nfs-server
● rpcbind.service - RPC bind service
   Loaded: loaded (/usr/lib/systemd/system/rpcbind.service; indirect; vendor preset: enabled)
   Active: active (running) since Thu 2017-06-08 15:38:46 CST; 15s ago
  Process: 3461 ExecStart=/sbin/rpcbind -w $RPCBIND_ARGS (code=exited, status=0/SUCCESS)
 Main PID: 3467 (rpcbind)
   CGroup: /system.slice/rpcbind.service
           └─3467 /sbin/rpcbind -w

Jun 08 15:38:46 nfs-server systemd[1]: Starting RPC bind service...
Jun 08 15:38:46 nfs-server systemd[1]: Started RPC bind service.

● nfs-server.service - NFS server and services
   Loaded: loaded (/usr/lib/systemd/system/nfs-server.service; enabled; vendor preset: disabled)
   Active: active (exited) since Thu 2017-06-08 15:38:57 CST; 5s ago
  Process: 3473 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS (code=exited, status=0/SUCCESS)
  Process: 3472 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS)
 Main PID: 3473 (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/nfs-server.service

Jun 08 15:38:57 nfs-server systemd[1]: Starting NFS server and services...
Jun 08 15:38:57 nfs-server systemd[1]: Started NFS server and services.
# 放通防火墙
[root@nfs-server ~]# firewall-cmd --add-service=nfs --permanent
success
[root@nfs-server ~]# firewall-cmd --reload
success

KVM存储池配置

1. 配置KVM宿主机连接NFS Server.

   [root@kvm-node1 ~]# yum install nfs-utils -y
   [root@kvm-node1 ~]# systemctl enable rpcbind && systemctl start rpcbind
   [root@kvm-node1 ~]# systemctl status rpcbind
   ● rpcbind.service - RPC bind service
      Loaded: loaded (/usr/lib/systemd/system/rpcbind.service; indirect; vendor preset: enabled)
      Active: active (running) since Thu 2017-06-08 15:56:56 CST; 16s ago
     Process: 8744 ExecStart=/sbin/rpcbind -w $RPCBIND_ARGS (code=exited, status=0/SUCCESS)
    Main PID: 8745 (rpcbind)
      CGroup: /system.slice/rpcbind.service
              └─8745 /sbin/rpcbind -w
   Jun 08 15:56:56 kvm-node1 systemd[1]: Starting RPC bind service...
   Jun 08 15:56:56 kvm-node1 systemd[1]: Started RPC bind service.
   [root@kvm-node1 ~]# mount -t nfs 192.168.57.200:/images /var/lib/libvirt/images
   [root@kvm-node1 ~]# df -hT
   Filesystem             Type      Size  Used Avail Use% Mounted on
   /dev/mapper/cl-root    xfs        17G  4.2G   13G  25% /
   devtmpfs               devtmpfs  478M     0  478M   0% /dev
   tmpfs                  tmpfs     489M   88K  489M   1% /dev/shm
   tmpfs                  tmpfs     489M  7.1M  482M   2% /run
   tmpfs                  tmpfs     489M     0  489M   0% /sys/fs/cgroup
   /dev/sda1              xfs      1014M  140M  875M  14% /boot
   tmpfs                  tmpfs      98M  8.0K   98M   1% /run/user/0
   192.168.57.200:/images nfs4       17G  4.2G   13G  25% /var/lib/libvirt/images
   [root@kvm-node1 ~]# echo -e "192.168.57.200:/images\t/var/lib/libvirt/images\tnfs\tdefaults\t0\t0" >> /etc/fstab
   

2. 配置KVM存储资源池

   [root@kvm-node1 ~]# virsh pool-list
    Name                 State      Autostart
   -------------------------------------------
   
   [root@kvm-node1 ~]# virsh pool-build default
   Pool default built
   
   [root@kvm-node1 ~]# virsh pool-start default
   Pool default started
   
   [root@kvm-node1 ~]# virsh pool-list
    Name                 State      Autostart
   -------------------------------------------
    default              active     yes
   
   [root@kvm-node1 ~]# virsh pool-info default
   Name:           default
   UUID:           d84dc74b-b0f4-4197-92b0-d9025620f0a4
   State:          running
   Persistent:     yes
   Autostart:      yes
   Capacity:       16.99 GiB
   Allocation:     4.10 GiB
   Available:      12.88 GiB
   
   [root@kvm-node1 ~]# df -Th /var/lib/libvirt/images/
   Filesystem             Type  Size  Used Avail Use% Mounted on
   192.168.57.200:/images nfs4   17G  4.2G   13G  25% /var/lib/libvirt/images