目前ubuntu的ulimit解决方案
/etc/systemd/system/set-ulimit.service
[Unit]
Description=Set ulimit for file descriptors
After=network.target
[Service]
Type=oneshot
ExecStart=/bin/bash -c "ulimit -n 65535"
RemainAfterExit=true
[Install]
WantedBy=multi-user.target启动设置65535