docker 问题

问题：Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

解决：docker 服务未启动，执行 systemctl start docker 启动 docker 服务

问题：Error response from daemon: Timeout was reached before node was joined. The attempt to join the swarm will continue in the background. Use the "docker info" command to see the current swarm status of your node.

解决：docker swarm init 返回的 ip地址是内网地址，另外节点加入的时候把对应的内网地址换成外网地址即可。

问题：WARNING: No swap limit support

解决：

1、/etc/default/grub 加入 GRUB_CMDLINE_LINUX="cgroup_enable=memory swapaccount=1"

2、更新 grub：sudo update-grub

3、重启：sudo reboot

因为要重启，所以没有尝试，不确定解决方案可行。

文档：https://docs.docker.com/config/containers/resource_constraints/#configure-the-realtime-scheduler

问题：Fatal error: Uncaught Error: Class 'mysqli' not found in Standard input code:22

解决：

问题：AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.20.0.4. Set the 'ServerName' directive globally to suppress this message