分类: LINUX
2015-11-07 23:23:14
docker是什么就不多说了,见。
docker容器最早受到RHEL完善的支持是从最近的CentOS 7.0开始的,官方说明是只能运行于64位架构平台,内核版本为2.6.32-431及以上(即>=CentOS 6.5,运行docker时实际提示3.8.0及以上),升级内核请参考CentOS 6.x 内核升级(2.6.32 -> 3.10.58)过程记录
需要注意的是CentOS
6.5与7.0的安装是有一点点不同的,CentOS-6上docker的安装包叫docker-io,并且来源于Fedora
epel库,这个仓库维护了大量的没有包含在发行版中的软件,所以先要安装EPEL,而CentOS-7的docker直接包含在官方镜像源的
Extras仓库(CentOS-Base.repo下的[extras]节enable=1启用)。前提是都需要联网,具体安装过程如下。
# getenforce enforcing # setenforce 0 permissive # vi /etc/selinux/config SELINUX=disabled
...
epel-release-6-8.noarch.rpm包在发行版的介质里面已经自带了,可以从rpm安装。
# yum install epel-release-6-8.noarch.rpm //或
yum -y install 6/x86_64/epel-release-6-8.noarch.rpm
如果出现GPG key retrieval failed: [Errno 14] Could not open/read file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6问题,请在线安装epel,下载RPM-GPG-KEY-EPEL-6文件。
这一步执行之后,会在/etc/yum.repos.d/下生成epel.repo、epel-testing.repo两个文件,用于从Fedora官网下载rpm包。
# uname -r 2.6.32-431.el6.x86_64 # cat /etc/redhat-release CentOS release 6.5 (Final)
看到这个最低的内核版本,事实运行起来是没太大问题的,你也可以升级到3.10.x版本。
另外你也可以运行脚本,来检查内核模块符不符合(下面有些missing的,我的docker还是可以正常启动):
[root@sean ~]# ./check-config
warning: /proc/config.gz does not exist, searching other paths for kernel config...
info: reading kernel config from /boot/config-2.6.32-431.el6.x86_64 ...
Generally Necessary: - cgroup hierarchy: properly mounted [/cgroup] - CONFIG_NAMESPACES: enabled - CONFIG_NET_NS: enabled - CONFIG_PID_NS: enabled - CONFIG_IPC_NS: enabled - CONFIG_UTS_NS: enabled - CONFIG_DEVPTS_MULTIPLE_INSTANCES: enabled - CONFIG_CGROUPS: enabled - CONFIG_CGROUP_CPUACCT: enabled - CONFIG_CGROUP_DEVICE: enabled - CONFIG_CGROUP_FREEZER: enabled - CONFIG_CGROUP_SCHED: enabled - CONFIG_MACVLAN: enabled - CONFIG_VETH: enabled - CONFIG_BRIDGE: enabled - CONFIG_NF_NAT_IPV4: missing - CONFIG_IP_NF_TARGET_MASQUERADE: enabled - CONFIG_NETFILTER_XT_MATCH_ADDRTYPE: missing - CONFIG_NETFILTER_XT_MATCH_CONNTRACK: enabled - CONFIG_NF_NAT: enabled - CONFIG_NF_NAT_NEEDED: enabled Optional Features: - CONFIG_MEMCG_SWAP: missing - CONFIG_RESOURCE_COUNTERS: enabled - CONFIG_CGROUP_PERF: enabled - Storage Drivers: - "aufs":
- CONFIG_AUFS_FS: missing
- CONFIG_EXT4_FS_POSIX_ACL: enabled
- CONFIG_EXT4_FS_SECURITY: enabled
- "btrfs":
- CONFIG_BTRFS_FS: enabled
- "devicemapper":
- CONFIG_BLK_DEV_DM: enabled
- CONFIG_DM_THIN_PROVISIONING: enabled
- CONFIG_EXT4_FS: enabled
- CONFIG_EXT4_FS_POSIX_ACL: enabled
- CONFIG_EXT4_FS_SECURITY: enabled
假如你是自己编译内核,请特别留意几个绝对不能缺少的:DM_THIN_PROVISIONING、IP_NF_TARGET_MASQUERADE、NF_NAT。(AUFS_FS没有对应选项,还不清楚怎么回事,但不是必须)
# yum install docker-io
Dependencies Resolved
===========================================================================================
Package Arch Version Repository Size ===========================================================================================
Installing:
docker-io x86_64 1.1.2-1.el6 epel 4.5 M
Installing for dependencies:
lua-alt-getopt noarch 0.7.0-1.el6 epel 6.9 k
lua-filesystem x86_64 1.4.2-1.el6 epel 24 k
lua-lxc x86_64 1.0.6-1.el6 epel 15 k
lxc x86_64 1.0.6-1.el6 epel 120 k
lxc-libs x86_64 1.0.6-1.el6 epel 248 k Transaction Summary
=========================================================================================== Install 6 Package(s)
许多文档介绍到这里,下一步为挂载/cgroup文件系统,我的docker版本为1.1.2,没有修改/etc/fstab的步骤。
# service docker start //或 # docker -d
在我的一次安装过程中,很不幸遇到下面的问题:
docker -d启动,或tail -f /var/log/docker查看日志
[f32e7d9f] +job initserver()
[f32e7d9f.initserver()] Creating server
[f32e7d9f] +job serveapi(unix:///var/run/docker.sock) 2014/10/22 13:02:45 Listening for HTTP on unix (/var/run/docker.sock) Error running DeviceCreate (createPool) dm_task_run failed
[f32e7d9f] -job initserver() = ERR (1) 2014/10/22 13:02:45 Error running DeviceCreate (createPool) dm_task_run failed
\nWed Oct 22 14:35:54 CST 2014\n
再或者是service docker restart
Stopping docker: [ OK ]
Starting cgconfig service: Error: cannot mount cpuset to /cgroup/cpuset: Device or resource busy
/sbin/cgconfigparser; error loading /etc/cgconfig.conf: Cgroup mounting failed
Failed to parse /etc/cgconfig.conf [FAILED]
Starting docker: [ OK ]
Unable to enable network bridge NAT: iptables failed: iptables -I POSTROUTING -t nat -s 172.17.42.1/16 ! -d 172.17.42.1/16 -j MASQUERADE: iptables v1.4.7: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
上面的三个异常都是由于内核模块的缺失导致的,这也是自己编译内核来升级带来的风险,于是就有了的kernel-ml-aufs的rpm包(见参考的第一个链接)。