docker使用问题总结

1. docker报【Error response from daemon: Error running DeviceCreate (createSnapDevice) dm_task_run failed】错

解决办法：

# systemctl stop docker.service
# thin_check /var/lib/docker/devicemapper/devicemapper/metadata

If there were no errors then proceed with:

# thin_check --clear-needs-check-flag /var/lib/docker/devicemapper/devicemapper/metadata
# systemctl start docker.service

If there were errors, you are on your own, but ‘man thin_check‘ and ‘man thin_repair‘ may be helpful...

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2. docker默认添加的iptables(ip相关的自己定制):

docker nat表部分：

docker0IP=`ifconfig docker0 |grep ‘inet‘ | cut -d ‘ ‘ -f 10`
iptables -A POSTROUTING -t nat -s $docker0IP/30 ! -o docker0 -j MASQUERADE

DockerChain="DOCKER" 
iptables -t nat -nL $DockerChain
if [ "x$?" != "x0" ] ; then
iptables -t nat -N $DockerChain
fi
iptables -A PREROUTING -m addrtype --dst-type LOCAL -t nat -j $DockerChain
iptables -A OUTPUT -m addrtype --dst-type LOCAL -t nat -j $DockerChain ! --dst 127.0.0.0/8

参考代码：
https://github.com/docker/docker/blob/2ad81da856c123acf91eeff7ab607376bd27d9ba/vendor/src/github.com/docker/libnetwork/drivers/bridge/setup_ip_tables.go
https://github.com/docker/docker/blob/2ad81da856c123acf91eeff7ab607376bd27d9ba/vendor/src/github.com/docker/libnetwork/iptables/iptables.go

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3.docker报类似如下错误【chown socket at step GROUP: No such process】，导致启动失败：

# journalctl -xn
-- Logs begin at Tue 2014-12-30 13:07:53 EST, end at Tue 2014-12-30 13:25:23 EST. --
Dec 30 13:12:30 ITX kernel: ip_tables: (C) 2000-2006 Netfilter Core Team
Dec 30 13:22:53 ITX systemd[1]: Starting Cleanup of Temporary Directories...
-- Subject: Unit systemd-tmpfiles-clean.service has begun with start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-tmpfiles-clean.service has begun starting up.
Dec 30 13:22:53 ITX systemd[1]: Started Cleanup of Temporary Directories.
-- Subject: Unit systemd-tmpfiles-clean.service has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-tmpfiles-clean.service has finished starting up.
--
-- The start-up result is done.
Dec 30 13:25:23 ITX systemd[1]: Starting Docker Socket for the API.
-- Subject: Unit docker.socket has begun with start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.socket has begun starting up.
Dec 30 13:25:23 ITX systemd[1868]: Failed to chown socket at step GROUP: No such process
Dec 30 13:25:23 ITX systemd[1]: docker.socket control process exited, code=exited status=216
Dec 30 13:25:23 ITX systemd[1]: Failed to listen on Docker Socket for the API.
-- Subject: Unit docker.socket has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.socket has failed.
--
-- The result is failed.
Dec 30 13:25:23 ITX systemd[1]: Dependency failed for Docker Application Container Engine.
-- Subject: Unit docker.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.service has failed.
--
-- The result is dependency.
Dec 30 13:25:23 ITX systemd[1]: Unit docker.socket entered failed state.

解决办法：

方法1.添加docker用户组（groupadd docker，如果/etc/group用统一配置管理的话记得在源group文件中添加docker组信息）

方法2.修改/usr/lib/systemd/system/docker.socket文件：

 

[Unit]
Description=Docker Socket for the API
PartOf=docker.service

 

[Socket]
ListenStream=/var/run/docker.sock
SocketMode=0660
SocketUser=root
SocketGroup=docker    这里改成：SocketGroup=root 或其他存在的组

 

[Install]
WantedBy=sockets.target

 

如下操作可选：

systemctl enable docker.service && systemctl enable docker.socket：

# systemctl list-unit-files | grep docker
docker.service disabled
docker.socket disabled

# chkconfig docker on #如果chkconfig不能使用则执行：systemctl enable docker.service
Note: Forwarding request to ‘systemctl enable docker.service‘.
ln -s ‘/usr/lib/systemd/system/docker.service‘ ‘/etc/systemd/system/multi-user.target.wants/docker.service‘

# systemctl list-unit-files|grep docker
docker.service enabled
docker.socket disabled

# systemctl enable docker.socket
ln -s ‘/usr/lib/systemd/system/docker.socket‘ ‘/etc/systemd/system/sockets.target.wants/docker.socket‘

# systemctl list-unit-files|grep docker
docker.service enabled
docker.socket enabled

参考链接：

http://www.milliondollarserver.com/?cat=7

http://www.milliondollarserver.com/?p=622

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4.当宿主机上只有一个容器时，删除容器有时会导致宿主机网路瞬断

解决方法：

1.修改/etc/sysconfig/ntpd配置文件增加"-L"选项，如

cat /etc/sysconfig/ntpd

# Command line options for ntpd

OPTIONS="-g -L"

2.重启ntpd服务：systemctl restart ntpd

参考链接：

https://access.redhat.com/solutions/261123

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5.docker1.6+按照官方文档搭建的私有registry， 但是docker login的时候报错

Username: ever
Password:
Email:
Error response from daemon: Unexpected status code [404] : <html>
<head><title>404 Not Found</title></head>
<body bgcolor="white">
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.6.3</center>
</body>
</html>

解决方法：大概说就是docker 1.6+ 需要registry 2.0, 此外还需要nginx的一个配置，而且这个配置官方文档错的，本来应该用set_more_header，文档用的add_header

官方v1 image和 v2 image迁移工具，可以看一下 https://github.com/docker/migrator，推荐书籍浙大的《docker 容器和容器云》

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6.docker1.8 pull镜像服务端的访问日志：

127.0.0.1 - - [16/Oct/2015:10:08:52 +0000] "GET /v2/ HTTP/1.1" 401 194 "-" "docker/1.8.3 go/go1.4.2 git-commit/f4bf5c7 kernel/4.2.0-1.el7.elrepo.x86_64 os/linux arch/amd64" "-"
127.0.0.1 - - [16/Oct/2015:10:08:52 +0000] "GET /v1/_ping HTTP/1.1" 404 168 "-" "docker/1.8.3 go/go1.4.2 git-commit/f4bf5c7 kernel/4.2.0-1.el7.elrepo.x86_64 os/linux arch/amd64" "-"
127.0.0.1 - - [16/Oct/2015:10:08:52 +0000] "POST /v1/users/ HTTP/1.1" 404 168 "-" "docker/1.8.3 go/go1.4.2 git-commit/f4bf5c7 kernel/4.2.0-1.el7.elrepo.x86_64 os/linux arch/amd64" "-"

docker应该访问v2接口却去访问v1的接口了

解决方法：docker和registry之间通过一个header来协商api的版本

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7.docker容器重启或宿主的iptables服务重启后容器无法接收到udp数据包（Failed to receive UDP traffic）：

原因：重启容器或重启宿主的iptables服务，在重启过程中，因为在某个时间点，对docker服务做的nat会因为重启失效，物理机会返回端口不可用（如：8888 port unreachable）的错误，这条返回会更新ip_conntrack表的缓存为类似这样：

ipv4     2 udp      17 29 src=xx.xx.xx.xx dst=xx.xx.xx.xx sport=xxxx dport=xxxx [UNREPLIED] src=xx.xx.xx.xx dst=xx.xx.xx.xx sport=xxxx dport=xxxx mark=0 zone=0 use=2 

从而导致iptables启动后，数据包再过来，也会依据已有的conntrack缓存，不会被转发到docker容器里面。

解决方法：清理conntrack缓存（可以使用conntrack-tool: conntrack -F）

相关链接：https://github.com/docker/docker/issues/8795       清理conntrack

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8.docker宿主机新增分区(/ssd)，docker必须重启，起容器时在该分区的数据卷(-v /ssd:/ssd)才能生效

解决方法（慎用）：修改/usr/lib/systemd/system/docker.service

[Unit]
Description=Docker Application Container Engine
Documentation=http://docs.docker.com
After=network.target docker.socket
Requires=docker.socket

[Service]
Type=notify
EnvironmentFile=-/etc/sysconfig/docker
EnvironmentFile=-/etc/sysconfig/docker-storage
ExecStart=/usr/bin/docker -d $OPTIONS $DOCKER_STORAGE_OPTIONS
ExecStartPost=/usr/bin/chmod 777 /var/run/docker.sock
LimitNOFILE=1048576
LimitNPROC=1048576
MountFlags=private   #将这里修改成 MountFlags=shared

[Install]
WantedBy=multi-user.target 

相关链接：https://huaminchen.wordpress.com/2015/05/19/how-docker-handles-mount-namespace/

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9.MFS+DOCKER的文件挂载问题

mfs在本地挂载如下
mfsmount /mnt -H ip -P port -S /
这样本地就有一个/mnt的mfs目录了
但是使用docker run -it -v /mnt:/mnt image:tags /bin/bash
之后发现容器内部还是本地的目录，并不是mfs的挂载目录。大小也不对。查看系统日志发现一个警告：
Jul 16 11:52:36 TENCENT64 docker: [error] mount.go:12 [warning]: couldn’t run auplink before unmount: exec: “auplink”: executable file not found
in $PATH

本地找不到这个auplink的命令，导致docker挂载异常，centos安装如下：
yum install aufs-util
然后需要重启docker
systemctl restart docker
重启容器就可以了

到现在为止docker挂载mfs总共莫名其妙的出过两次问题：

1.mfs修改了挂载目录，但是没有重启docker,结果不论如何启动，抓取日志，依旧没有办法在docker容器中看到mfs的挂载目录。

2.在启动进入容器之后，删除了大量的文件，操作过程已经结束，但是mfs有回收站机制，文件没放到了回收站，真正的数据清理其实并没有进行。这个状态你可以在mfs.cgi页面可以看到。结果在容器中mkdir创建文件夹的时候报device is busy.

这两个错误，我都是重启docker之后才解决的。我认为可能是docker底层的文件服务，cgroup或者aufs有点问题。这个问题暂且留着。

其他网友总结的问题 

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10.docker v1版私有仓库，镜像第一次上传时索引写入db,但是镜像上传失败（search可以找到，但是delete接口删除失败），仓库报错如下：

原因：索引已经写入db，但是镜像上传失败，此时会再次写入索引，进而引起name不唯一的报错

解决方法：索引存在sqlite数据库中，去数据库中把报错的镜像索引删掉即可(sqlite3 docker-registry.db;.tables;select * from repository;)。

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11.device mapper discard的宕机。

原因：这个问题反复出现在某些服务器上，宕机重启后通过IPMI consule进入时系统已经重新挂载了CoreDump的Kernel，看到CoreDump生成dump之前进行Recover操作和Data Copying操作，导致恢复时间很慢。通过Coredump分析属于Kernel在DM discard方面的一个BUG，方法为禁用docker devicemapper的discard。

解决方法：设置docker启动参数"--storage-opt dm.mountopt=nodiscard --storage-opt dm.blkdiscard=false"

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12.docker启动报错[error] attach_loopback.go:42 There are no more loopback devices available，完整错误日志：

systemd[1]: Starting Docker Application Container Engine...
docker[47518]: 2016/02/03 14:50:32 docker daemon: 1.3.2 39fa2fa/1.3.2; execdriver: native; graphdriver:
docker[47518]: [b98612a1] +job serveapi(fd://, tcp://0.0.0.0:2375, unix:///var/run/docker.sock)
docker[47518]: [error] attach_loopback.go:42 There are no more loopback devices available.
docker[47518]: 2016/02/03 14:50:32 loopback mounting failed
systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
systemd[1]: Failed to start Docker Application Container Engine.
systemd[1]: Unit docker.service entered failed state.
systemd[1]: docker.service failed.

原因：because your host system does not have the loopback files in it‘s dev for docker to use.

解决方法：Use something like this on your host then run the container and it will pick up the devices.

#!/bin/bash

for i in {0..6}

do

    mknod -m0660 /dev/loop$i b 7 $i

done

docker 官方issue：git issue

 

=========================其他链接================================

 

Linux内核bug引起Mesos、Kubernetes、Docker的TCP/IP数据包失效

docker容器根目录为只读的解决办法