How to start Docker for Mac daemon on boot?

Question

I want to have Docker for Mac start on boot, not on login. How do I do this? I'd like to create a LaunchDaemon, I just don't know what program to start.

All the examples I see seem to use docker-machine to define a VM, but the documentation now says that docker-machine is now not the way to go if you want to use the default VM created when Docker is installed, as Docker for Mac doesn't use docker-machine to create the VM.

The reason is that I want to start Docker to run Jenkins and Nexus containers on boot, as the server is going to be used as a CI server. The Docker GUI has the preference option of starting on login, which is not the same thing as on boot.

I am running OSX Sierra.

Answer 1

TL;DR Running Docker for Mac as a standalone service is not supported.

Instead run Docker in a VirtualBox VM, either by creating a plain VM or using docker-machine. Then set the Virtualbox VM up to run at boot

Attempted setup with Docker for Mac

The Docker for Mac application creates a launchd service:

○→ launchctl list | grep -i docker
-   0   com.docker.helper
78105   0   com.docker.docker.52512

The service has the following details:

○→ launchctl list com.docker.docker.52512
{
    "LimitLoadToSessionType" = "Aqua";
    "Label" = "com.docker.docker.52512";
    "TimeOut" = 30;
    "OnDemand" = true;
    "LastExitStatus" = 0;
    "PID" = 78105;
    "Program" = "/Applications/Docker.app/Contents/MacOS/Docker";
    "ProgramArguments" = (
        "/Applications/Docker.app/Contents/MacOS/Docker";
    );
    "PerJobMachServices" = {
        "com.apple.tsm.portname" = mach-port-object;
        "com.apple.CFPasteboardClient" = mach-port-object;
        "com.apple.coredrag" = mach-port-object;
        "com.apple.axserver" = mach-port-object;
    };
};

And has the following process tree:

○→ pstree -p 78105
-+= 00001 root /sbin/launchd
 \-+= 78105 matt /Applications/Docker.app/Contents/MacOS/Docker
   \-+= 78118 matt /Applications/Docker.app/Contents/MacOS/com.docker.osx.hyperkit.linux -watchdog fd:0 -max-restarts 5 -restart-seconds 30
     |--- 78119 matt /Applications/Docker.app/Contents/MacOS/com.docker.osx.hyperkit.linux -watchdog fd:0 -max-restarts 5 -restart-seconds 30
     |--= 78120 matt com.docker.db --url fd://3 --git /Users/matt/Library/Containers/com.docker.docker/Data/database
     |--= 78121 matt com.docker.osxfs --address fd:3 --connect /Users/matt/Library/Containers/com.docker.docker/Data/@connect --control fd:4 --volume-control
     |--= 78122 matt com.docker.slirp --db /Users/matt/Library/Containers/com.docker.docker/Data/s40 --ethernet fd:3 --port fd:4 --introspection fd:5 --diagn
     |-+= 78123 matt com.docker.osx.hyperkit.linux
     | \--- 78125 matt /Applications/Docker.app/Contents/MacOS/com.docker.osx.hyperkit.linux
     \-+= 78124 matt com.docker.driver.amd64-linux -db /Users/matt/Library/Containers/com.docker.docker/Data/s40 -osxfs-volume /Users/matt/Library/Containers
       |--- 78126 matt /Applications/Docker.app/Contents/MacOS/com.docker.driver.amd64-linux -db /Users/matt/Library/Containers/com.docker.docker/Data/s40 -o
       \--- 78130 matt /Applications/Docker.app/Contents/MacOS/com.docker.hyperkit -A -m 2048M -c 3 -u -s 0:0,hostbridge -s 31,lpc -s 2:0,virtio-vpnkit,uuid=

The first problem is /Applications/Docker.app/Contents/MacOS/Docker is the GUI app that sits in your tray rather than the VM, so that's going to be hard to run at boot time. The first descendant /Applications/Docker.app/Contents/MacOS/com.docker.osx.hyperkit.linux looks more like something that manages the VM so we'll start there.

Get the full command of the hyperkit process

○→ ps -fp 78105
  UID   PID  PPID   C STIME   TTY           TIME CMD
  501 78105 82644   0  2:08am ??         0:00.03 /Applications/Docker.app/Contents/MacOS/com.docker.osx.hyperkit.linux -watchdog fd:0 -max-restarts 5 -restart-seconds 30

Get the working directory of the process

○→ sudo lsof -p 78105 | grep cwd
com.docke 78105 matt  cwd      DIR                1,4       748 63186601 /Users/matt/Library/Containers/com.docker.docker/Data

Create a launchd plist file /Library/LaunchDaemons/com.you.docker.plist containing the details

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
    <string>com.you.docker</string>
  <key>ProgramArguments</key>
    <array>
      <string>/Applications/Docker.app/Contents/MacOS/com.docker.osx.hyperkit.linux</string>
      <string>-watchdog</string>
      <string>fd:0</string>
      <string>-max-restarts</string>
      <string>5</string>
      <string>-restart-seconds</string>
      <string>30</string>
    </array>
  <key>UserName</key>
    <string>youruser</string>
  <key>WorkingDirectory</key>
    <string>/Users/youruser/Library/Containers/com.docker.docker/Data</string>
  <key>RunAtLoad</key>
    <true/>
</dict>
</plist>

Which you can load with

sudo launchctl load -w /Library/LaunchDaemons/com.you.docker.plist

Then... nothing. Check the logs

○→ tail /var/log/system.log
Mar  7 02:23:26 mac Docker[87728]: Acquired task manager lock
Mar  7 02:23:26 mac Docker[87728]: Maximum number of file descriptors is 10240
Mar  7 02:23:26 mac Docker[87728]: Failed to read watchdog handshake
Mar  7 02:23:26 mac com.apple.xpc.launchd[1] (com.you.docker[87728]): Service exited with abnormal code: 1

You'll notice the command we are running specifies an option -watchdog fd:0 which will be the stdin of the hyperkit process so there is probably something missing.

If I run Docker normally again and look at what FD 0 is for the hyperkit process when it's working

○→ sudo lsof -p 88360
COMMAND     PID USER   FD     TYPE             DEVICE  SIZE/OFF     NODE NAME
com.docke 88360 matt    0     PIPE 0xff80ce577ca2ed91     16384          ->0xff80ce5776aa8d51

Then looking at PIPE 0xff80ce577ca2ed91 across the system you'll see the main Docker process has the pipe open for many processes.

○→ sudo lsof | grep 0xff80ce577ca2ed91
COMMAND     PID             USER   FD      TYPE             DEVICE    SIZE/OFF     NODE NAME
Docker    88349             matt   13      PIPE 0xff80ce5776aa8d51       16384          ->0xff80ce577ca2ed91
com.docke 88360             matt    0      PIPE 0xff80ce577ca2ed91       16384          ->0xff80ce5776aa8d51
com.docke 88362             matt    0      PIPE 0xff80ce577ca2ed91       16384          ->0xff80ce5776aa8d51
com.docke 88363             matt    0      PIPE 0xff80ce577ca2ed91       16384          ->0xff80ce5776aa8d51
com.docke 88364             matt    0      PIPE 0xff80ce577ca2ed91       16384          ->0xff80ce5776aa8d51
com.docke 88365             matt    0      PIPE 0xff80ce577ca2ed91       16384          ->0xff80ce5776aa8d51
com.docke 88366             matt    0      PIPE 0xff80ce577ca2ed91       16384          ->0xff80ce5776aa8d51

Trying to load the service again without the -watchdog fd:0 options results in the same error.

So it looks like the main Docker app does some setup that is required to run the VM. I haven't been able to find the source code for whatever deals with the watchdog option so not sure what it expects.

Maybe raise an issue or feature request on https://github.com/docker/for-mac to get the details of running the VM standalone from the App.