January 19, 2016

docker使用小记

funtooWiki上有一篇非常好的文章介绍内核配置及lxc的配置。[1]

错误说明

  1. 运行命令docker run centos echo 'hello world'结果提示出错：

    lxc-start: Device or resource busy - failed to mount a new instance of
'/dev/pts'
lxc-start: failed to setup the new pts instance
lxc-start: failed to setup the container
lxc-start: invalid sequence number 1. expected 2

    根据错误提示应该是使用/dev/pts失败，检查一下lxc的配置文件，结果发现/etc/lxc目录下为空，也就是说lxc使用的默认配置。再检查一下发现有一个命令lxc-checkconfig可以检查lxc的配置，运行一下得到：

    --- Namespaces ---
Namespaces: enabled
Utsname namespace: enabled
Ipc namespace: enabled
Pid namespace: enabled
User namespace: enabled
Network namespace: enabled
Multiple /dev/pts instances: missing

--- Control groups ---
Cgroup: enabled
Cgroup clone_children flag: enabled
Cgroup device: enabled
Cgroup sched: enabled
Cgroup cpu account: enabled
Cgroup memory controller: missing
Cgroup cpuset: enabled

--- Misc ---
Veth pair device: enabled
Macvlan: enabled
Vlan: enabled
File capabilities: enabled

Note : Before booting a new kernel, you can check its configuration
usage : CONFIG=/path/to/config /usr/sbin/lxc-checkconfig

    从配置文件检查可以发现Multiple /dev/pts和Cgroup memory controller两功能不支持，经google，应该是内核配置的问题。[2]重新配置相应内核选项，并编译即可。

    │ Symbol: DEVPTS_MULTIPLE_INSTANCES [=y]
│ Type  : boolean
│ Prompt: Support multiple instances of devpts
│   Location:
│     -> Device Drivers
│       -> Character devices
│         -> Enable TTY (TTY [=y])
│ (1)       -> Unix98 PTY support (UNIX98_PTYS [=y])
│   Defined at drivers/tty/Kconfig:123
│   Depends on: TTY [=y] && UNIX98_PTYS [=y]
Posted by LiuHui
Filed under: devops, learn, docker
Tags: learn, devops, docker, cloud, 潮流