Logs and troubleshooting

Estimated reading time: 14 minutes

Here is information about how to diagnose and troubleshoot problems, send logs and communicate with the Docker for Mac team, use our forums and Knowledge Hub, browse and log issues on GitHub, and find workarounds for known problems.

Docker Knowledge Hub

Looking for help with Docker for Mac? Check out the Docker Knowledge Hub for knowledge base articles, FAQs, and technical support for various subscription levels.

Diagnose problems, send feedback, and create GitHub issues

If you encounter problems for which you do not find solutions in this documentation, Docker for Mac issues on GitHub already filed by other users, or on the Docker for Mac forum, we can help you troubleshoot the log data.

Choose –> Diagnose & Feedback from the menu bar.

Diagnose problems

You can choose to run diagnostics only, or diagnose and send the results to the Docker Team:

  • Diagnose Only - Runs diagnostics, and shows results locally. (Results are not sent to Docker, and no ID is generated.)

Diagnostic results only

  • Diagnose & Upload - Runs diagnostics, shows results, and auto-uploads the diagnostic results to Docker. A diagnostic ID is auto-generated. You can refer to this ID when communicating with the Docker Team. Optionally, you can open an issue on GitHub using the uploaded results and ID as a basis.

Diagnostics & Feedback

If you click Open Issues, this opens Docker for Mac issues on GitHub in your web browser in a “create new issue” template prepopulated with the following:

  • ID and summary of the diagnostic you just ran

  • System and version details

  • Sections where you can fill in a description of expected and actual behavior, and steps to reproduce the issue

Create issue on GitHub

You can also create a new issue directly on GitHub at https://github.com/docker/for-mac/issues. (The README for the repository is here.)

Click New Issue on that page (or right here ☺) to get a “create new issue” template prepopulated with sections for the ID and summary of your diagnostics, system and version details, description of expected and actual behavior, and steps to reproduce the issue.

issue template

Checking the logs

In addition to using the diagnose and feedback option to submit logs, you can browse the logs yourself.

Use the command line to view logs

To view Docker for Mac logs at the command line, type this command in a terminal window or your favorite shell.

$ syslog -k Sender Docker

Alternatively, you can send the output of this command to a file. The following command redirects the log output to a file called my_docker_logs.txt.

$ syslog -k Sender Docker > ~/Desktop/my_docker_logs.txt

Use the Mac Console for log queries

Macs provide a built-in log viewer. You can use the Mac Console System Log Query to check Docker app logs.

The Console lives on your Mac hard drive in Applications > Utilities. You can bring it up quickly by just searching for it with Spotlight Search.

To find all Docker app log messages, do the following.

  1. From the Console menu, choose File > New System Log Query…

    Mac Console search for Docker app

    • Name your search (for example Docker)
    • Set the Sender to Docker
  2. Click OK to run the log query.

Mac Console display of Docker app search results

You can use the Console Log Query to search logs, filter the results in various ways, and create reports.

For example, you could construct a search for log messages sent by Docker that contain the word hypervisor then filter the results by time (earlier, later, now).

The diagnostics and usage information to the left of the results provide auto-generated reports on packages.

Troubleshooting

Docker for Mac will not start if Mac user account and home folder are renamed after installing the app

If, after installing Docker for Mac, you change the name of your macOS user account and home folder, Docker for Mac will fail to start. To solve this problem, uninstall then reinstall Docker for Mac under the new user account.

See also, the discussion on the issue docker/for-mac#1209 and Do I need to reinstall Docker for Mac if I change the name of my macOS account? in the FAQs.

Volume mounting requires file sharing for any project directories outside of /Users

If you are using mounted volumes and get runtime errors indicating an application file is not found, a volume mount is denied, or a service cannot start (e.g., with Docker Compose), you might need to enable file sharing.

Volume mounting requires shared drives for projects that live outside of the /Users directory. Go to –> Preferences –> File sharing and share the drive that contains the Dockerfile and volume.

Recreate or update your containers after Beta 18 upgrade

Docker 1.12.0 RC3 release introduces a backward incompatible change from RC2 to RC3. (For more information, see [https://github.com/moby/moby/issues/24343#issuecomment-230623542] (https://github.com/moby/moby/issues/24343#issuecomment-230623542).)

You may get the following error when you try to start a container created with pre-Beta 18 Docker for Mac applications.

		Error response from daemon: Unknown runtime specified default

You can fix this by either recreating or updating your containers.

If you get the error message shown above, we recommend recreating them.

Recreate your containers

To recreate your containers, use Docker Compose.

		docker-compose down && docker-compose up

Update your containers

To fix existing containers, follow these steps.

  1. Run this command.

         $ docker run --rm -v /var/lib/docker:/docker cpuguy83/docker112rc3-runtimefix:rc3
    
         Unable to find image 'cpuguy83/docker112rc3-runtimefix:rc3' locally
         rc3: Pulling from cpuguy83/docker112rc3-runtimefix
         91e7f9981d55: Pull complete
         Digest: sha256:96abed3f7a7a574774400ff20c6808aac37d37d787d1164d332675392675005c
         Status: Downloaded newer image for cpuguy83/docker112rc3-runtimefix:rc3
         proccessed 1648f773f92e8a4aad508a45088ca9137c3103457b48be1afb3fd8b4369e5140
         skipping container '433ba7ead89ba645efe9b5fff578e674aabba95d6dcb3910c9ad7f1a5c6b4538': already fixed
         proccessed 43df7f2ac8fc912046dfc48cf5d599018af8f60fee50eb7b09c1e10147758f06
         proccessed 65204cfa00b1b6679536c6ac72cdde1dbb43049af208973030b6d91356166958
         proccessed 66a72622e306450fd07f2b3a833355379884b7a6165b7527c10390c36536d82d
         proccessed 9d196e78390eeb44d3b354d24e25225d045f33f1666243466b3ed42fe670245c
         proccessed b9a0ecfe2ed9d561463251aa90fd1442299bcd9ea191a17055b01c6a00533b05
         proccessed c129a775c3fa3b6337e13b50aea84e4977c1774994be1f50ff13cbe60de9ac76
         proccessed dea73dc21126434f14c58b83140bf6470aa67e622daa85603a13bc48af7f8b04
         proccessed dfa8f9278642ab0f3e82ee8e4ad029587aafef9571ff50190e83757c03b4216c
         proccessed ee5bf706b6600a46e5d26327b13c3c1c5f7b261313438d47318702ff6ed8b30b
    
  2. Quit Docker.

  3. Start Docker.

    Note: Be sure to quit and then restart Docker for Mac before attempting to start containers.

  4. Try to start the container again:

             $ docker start old-container
             old-container
    

Incompatible CPU detected

Docker for Mac requires a processor (CPU) that supports virtualization and, more specifically, the Apple Hypervisor framework. Docker for Mac is only compatible with Macs that have a CPU that supports the Hypervisor framework. Most Macs built in 2010 and later support it, as described in the Apple Hypervisor Framework documentation about supported hardware:

Generally, machines with an Intel VT-x feature set that includes Extended Page Tables (EPT) and Unrestricted Mode are supported.

To check if your Mac supports the Hypervisor framework, run this command in a terminal window.

sysctl kern.hv_support If your Mac supports the Hypervisor Framework, the command will print kern.hv_support: 1.

If not, the command will print kern.hv_support: 0.

See also, Hypervisor Framework Reference in the Apple documentation, and Docker for Mac system requirements in What to know before you install.

Workarounds for common problems

  • IPv6 workaround to auto-filter DNS addresses - IPv6 is not yet supported on Docker for Mac, which typically manifests as a network timeout when running docker commands that need access to external network servers (e.g., docker pull busybox).

      $ docker pull busybox
      Using default tag: latest
      Pulling repository docker.io/library/busybox
      Network timed out while trying to connect to https://index.docker.io/v1/repositories/library/busybox/images. You may want to check your internet connection or if you are behind a proxy.
    

    Starting with v1.12.1, 2016-09016 on the stable channel, and Beta 24 on the beta channel, a workaround is provided that auto-filters out the IPv6 addresses in DNS server lists and enables successful network accesss. For example, 2001:4860:4860::8888 would become 8.8.8.8. So, the only workaround action needed for users is to upgrade to Docker for Mac stable v1.12.1 or newer, or Beta 24 or newer.

    On releases with the workaround included to filter out / truncate IPv6 addresses from the DNS list, the above command should run properly:

      $ docker pull busybox
      Using default tag: latest
      latest: Pulling from library/busybox
      Digest: sha256:a59906e33509d14c036c8678d687bd4eec81ed7c4b8ce907b888c607f6a1e0e6
      Status: Image is up to date for busy box:latest
    

    To learn more, see these issues on GitHub and Docker for Mac forums:

  • If Docker for Mac fails to install or start properly:

    • Make sure you quit Docker for Mac before installing a new version of the application ( –> Quit Docker). Otherwise, you will get an “application in use” error when you try to copy the new app from the .dmg to /Applications.

    • Restart your Mac to stop / discard any vestige of the daemon running from the previously installed version.

    • Run the uninstall commands from the menu.

  • If docker commands aren’t working properly or as expected:

    • Make sure you are not using the legacy Docker Machine environment in your shell or command window. You do not need DOCKER_HOST set, so unset it as it may be pointing at another Docker (e.g. VirtualBox). If you use bash, unset ${!DOCKER_*} will unset existing DOCKER environment variables you have set.

    • For other shells, unset each environment variable individually as described in Setting up to run Docker for Mac in Docker for Mac vs. Docker Toolbox.

  • Note that network connections will fail if the macOS Firewall is set to “Block all incoming connections”. You can enable the firewall, but bootpd must be allowed incoming connections so that the VM can get an IP address.

  • For the hello-world-nginx example, Docker for Mac must be running in order to get to the webserver on http://localhost/. Make sure that the Docker whale is showing in the menu bar, and that you run the Docker commands in a shell that is connected to the Docker for Mac Engine (not Engine from Toolbox). Otherwise, you might start the webserver container but get a “web page not available” error when you go to localhost. For more on distinguishing between the two environments, see Docker for Mac vs. Docker Toolbox.

  • If you see errors like Bind for 0.0.0.0:8080 failed: port is already allocated or listen tcp:0.0.0.0:8080: bind: address is already in use:

    • These errors are often caused by some other software on the Mac using those ports.

    • Run lsof -i tcp:8080 to discover the name and pid of the other process and decide whether to shut the other process down, or to use a different port in your docker app.

Known issues

  • IPv6 is not yet supported on Docker for Mac. If you are using IPv6, and haven’t upgraded to Beta 24 or v1.12.1 stable or newer, you will see a network timeout when you run docker commands that need access to external network servers. The aforementioned releases include a workaround for this because Docker for Mac does not yet support IPv6. See “IPv6 workaround to auto-filter DNS addresses” in Workarounds for common problems.

  • You might encounter errors when using docker-compose up with Docker for Mac (ValueError: Extra Data). We’ve identified this is likely related to data and/or events being passed all at once rather than one by one, so sometimes the data comes back as 2+ objects concatenated and causes an error.

  • Force-ejecting the .dmg after running Docker.app from it results in an unresponsive whale in the menu bar, Docker tasks “not responding” in activity monitor, helper processes running, and supporting technologies consuming large percentages of CPU. Please reboot, and then re-start Docker for Mac. If needed,force quit any Docker related applications as part of the reboot.

  • Docker does not auto-start on login even when it is enabled in –> Preferences. This is related to a set of issues with Docker helper, registration, and versioning.

  • Docker for Mac uses the HyperKit hypervisor (https://github.com/docker/hyperkit) in macOS 10.10 Yosemite and higher. If you are developing with tools that have conflicts with HyperKit, such as Intel Hardware Accelerated Execution Manager (HAXM), the current workaround is not to run them at the same time. You can pause HyperKit by quitting Docker for Mac temporarily while you work with HAXM. This will allow you to continue work with the other tools and prevent HyperKit from interfering.

  • If you are working with applications like Apache Maven that expect settings for DOCKER_HOST and DOCKER_CERT_PATH environment variables, specify these to connect to Docker instances through Unix sockets. For example:

     export DOCKER_HOST=unix:///var/run/docker.sock
    
  • docker-compose 1.7.1 performs DNS unnecessary lookups for localunixsocket.local which can take 5s to timeout on some networks. If docker-compose commands seem very slow but seem to speed up when the network is disabled (e.g. when disconnected from wifi), try appending 127.0.0.1 localunixsocket.local to the file /etc/hosts. Alternatively you could create a plain-text TCP proxy on localhost:1234 using:

      docker run -d -v /var/run/docker.sock:/var/run/docker.sock -p 127.0.0.1:1234:1234 bobrik/socat TCP-LISTEN:1234,fork UNIX-CONNECT:/var/run/docker.sock
    
    and then `export DOCKER_HOST=tcp://localhost:1234`.
    

  • There are a number of issues with the performance of directories bind-mounted with osxfs. In particular, writes of small blocks, and traversals of large directories are currently slow. Additionally, containers that perform large numbers of directory operations, such as repeated scans of large directory trees, may suffer from poor performance. Applications that behave in this way include:

    • rake
    • ember build
    • Symfony
    • Magento
    • Zend Framework
    • PHP applications that use Composer to install dependencies in a vendor folder

    As a work-around for this behavior, you can put vendor or third-party library directories in Docker volumes, perform temporary file system operations outside of osxfs mounts, and use third-party tools like Unison or rsync to synchronize between container directories and bind-mounted directories. We are actively working on osxfs performance using a number of different techniques. To learn more, please see the topic on Performance issues, solutions, and roadmap.

  • If your system does not have access to an NTP server, then after a hibernate the time seen by Docker for Mac may be considerably out of sync with the host. Furthermore, the time may slowly drift out of sync during use. To manually reset the time after hibernation, run:

      docker run --rm --privileged alpine hwclock -s
    

    Or, to resolve both issues, you can add the local clock as a low-priority (high stratum) fallback NTP time source for the host. To do this, edit the host’s /etc/ntp-restrict.conf to add:

      server 127.127.1.1              # LCL, local clock
      fudge  127.127.1.1 stratum 12   # increase stratum
    

    Then restart the NTP service with:

      sudo launchctl unload /System/Library/LaunchDaemons/org.ntp.ntpd.plist
      sudo launchctl load /System/Library/LaunchDaemons/org.ntp.ntpd.plist
    
mac, troubleshooting, logs, issues