作者：Hank FU 付汉杰 hankf@xilinx.com，来源： 赛灵思中文社区论坛
测试环境
Xilinx ZCU106 单板
Xilinx VCU TRD2020.1
Linux 内核配置
根据文档Docker on Zynq Ultrascale+ (Xilinx Yocto Flow)，在PetaLinux工程的文件project-spec/meta-user/recipes-kernel/linux/linux-xlnx/user.cfg里添加下列配置项。
CONFIG_NAMESPACES=y CONFIG_NET_NS=y CONFIG_PID_NS=y CONFIG_IPC_NS=y CONFIG_UTS_NS=y CONFIG_CGROUP_CPUACCT=y CONFIG_CGROUP_DEVICE=y CONFIG_CGROUP_FREEZER=y CONFIG_CGROUP_SCHED=y CONFIG_CPUSETS=y CONFIG_MEMCG=y CONFIG_VETH=y CONFIG_IP_NF_TARGET_MASQUERADE=y CONFIG_NETFILTER_XT_MATCH_ADDRTYPE=y CONFIG_NETFILTER_XT_MATCH_IPVS=y CONFIG_IP_NF_NAT=y CONFIG_USER_NS=y CONFIG_SECCOMP=y CONFIG_CGROUP_PIDS=y CONFIG_MEMCG_SWAP=y CONFIG_MEMCG_SWAP_ENABLED=y CONFIG_BLK_CGROUP=y CONFIG_BLK_DEV_THROTTLING=y CONFIG_CFQ_GROUP_IOSCHED=y CONFIG_CGROUP_PERF=y CONFIG_CGROUP_HUGETLB=y CONFIG_NET_CLS_CGROUP=y CONFIG_CGROUP_NET_PRIO=y CONFIG_CFS_BANDWIDTH=y CONFIG_FAIR_GROUP_SCHED=y CONFIG_RT_GROUP_SCHED=y CONFIG_IP_NF_TARGET_REDIRECT=y CONFIG_IP_VS=y CONFIG_IP_VS_NFCT=y CONFIG_IP_VS_PROTO_TCP=y CONFIG_IP_VS_PROTO_UDP=y CONFIG_IP_VS_RR=y CONFIG_EXT3_FS_XATTR=y CONFIG_EXT3_FS_POSIX_ACL=y CONFIG_EXT3_FS_SECURITY=y CONFIG_VXLAN=y CONFIG_INET_ESP=y CONFIG_IPVLAN=y CONFIG_MACVLAN=y CONFIG_DUMMY=y CONFIG_NF_NAT_FTP=y CONFIG_NF_CONNTRACK_FTP=y CONFIG_NF_NAT_TFTP=y CONFIG_NF_CONNTRACK_TFTP=y CONFIG_AUFS_FS=y CONFIG_BTRFS_FS_POSIX_ACL=y CONFIG_BLK_DEV_DM=y CONFIG_DM_THIN_PROVISIONING=y CONFIG_OVERLAY_FS=y CONFIG_MD=y CONFIG_NET_SCHED=y CONFIG_NET_L3_MASTER_DEV=y CONFIG_BRIDGE=m # CONFIG_EXT2_FS is not set CONFIG_EXT4_USE_FOR_EXT2=y
Linux 文件系统配置
在PetaLinux工程里选择Packagegroup-petalinux-ocicontainers。
启动命令
使用命令“dockerd &”可以启动Docker。运行之前，要先导出变量DOCKER_RAMDISK。
export DOCKER_RAMDISK=true
测试命令
使用命令“docker run --rm hello-world”可以运行一个简单容器。
常见问题 网络权限
单板要有访问网络权限，要能下载Docker的镜像。
root@vcu_trd:~# docker run --rm hello-world Unable to find image 'hello-world:latest' locally WARN[2020-11-11T09:47:14.257031091Z] Could not get operating system name: Error opening /usr/lib/os-release: open /usr/lib/os-release: no such file or directory WARN[2020-11-11T09:47:14.286697565Z] Error getting v2 registry: Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io on [::1]:53: read udp [::1]:41143->[::1]:53: read: connection refused INFO[2020-11-11T09:47:14.286851881Z] Attempting next endpoint for pull after error: Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io on [::1]:53: read udp [::1]:41143->[::1]:53: read: connection refused ERRO[2020-11-11T09:47:14.287032029Z] Handler for POST /v1.40/images/create returned error: Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io on [::1]:53: read udp [::1]:41143->[::1]:53: read: connection refused docker: Error response from daemon: Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io on [::1]:53: read udp [::1]:41143->[::1]:53: read: connection refused. See 'docker run --help'.
存储空间
单板上可能缺乏足够存储空间。可以使用dockerd的选项data-root指定一个有足够空间的目录给dockerd使用。
#ERROR Download failed: write /var/lib/docker/tmp/GetImageBlob091922966: no space left on device
docker启动失败
另外，docker启动过程中，可能没能启动containerd，出现下列错误。
root@vcu_trd:/run/test# docker run --rm hello-world docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?. See 'docker run --help'. root@vcu_trd:/run/test# docker-compose pull ERROR: Couldn't connect to Docker daemon at http+docker://localhost - is it running? If it's at a non-standard location, specify the URL with the DOCKER_HOST environment variable.
这时候可以杀死dockerd进程，再次启动dockerd。可以借助下列命令来快速杀死dockerd进程和启动dockerd。
CONTAINERD_PID=$(ps -A | grep -v grep | grep containerd | grep -v .sh |awk '{printf $1}')
DOCKERD_PID=$(ps -A | grep -v grep | grep dockerd | grep -v .sh |awk '{printf $1}')
echo -e "containerd PID: $CONTAINERD_PID\n" | tee -a $docker_log_file
echo -e "dockerd PID: $DOCKERD_PID\n" | tee -a $docker_log_file
if [ ! "$CONTAINERD_PID" = "" ]; then
echo -e "kill containerd PID: $CONTAINERD_PID\n" | tee -a $docker_log_file
kill $CONTAINERD_PID
fi
if [ ! "$DOCKERD_PID" = "" ]; then
echo -e "kill dockerd PID: $DOCKERD_PID\n" | tee -a $docker_log_file
kill $DOCKERD_PID
# Error starting daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid
rm -f /var/run/docker.pid | tee -a $docker_log_file
fi
sleep 1
echo -e "\nStart Docker...\n" | tee -a $docker_log_file
ls -l /run/docker | tee -a $docker_log_file
mkdir -p /run/docker/data | tee -a $docker_log_file
dockerd --data-root /run/docker/data | tee -a $docker_log_file &
sleep 12
ps -A | grep docker | tee -a $docker_log_file
ps -A | grep containerd | tee -a $docker_log_file
ls -l /var/run/docker.sock | tee -a $docker_log_file
#docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.
echo -e "\nRun Docker hello-world...\n" | tee -a $docker_log_file
docker run --rm hello-world | tee -a $docker_log_file文件/var/run/docker.pid已经存在
启动启动dockerd时，可能报错，说文件/var/run/docker.pid已经存在。重启动dockerd时，需要先删除文件/var/run/docker.pid。
# Error starting daemon: pid file found, ensure docker is not running or delete /var/run/docker.pid
参考文档
https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/84508673/Docker+on...
