DC/OS 1.9.0 Release Candidate 3

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DC/OS 1.9 includes many new capabilities for Operators, and expands the collection of Data and Developer Services with a focus on:

  • Tools for Production Operations - Monitoring and troubleshooting for distributed apps.
  • Broader Workload Support - From traditional apps to machine learning.
  • New data and developer services.


What's New

Apache Mesos 1.2 and Marathon 1.4 integrated

Container Orchestration

  • Pods - Multiple co-located containers per instance, scheduled on the same host. For more information, see the documentation.
  • GPU - Leverage GPUs to run novel algorithms. For more information, see the documentation.
  • Significant scalability improvements.

DC/OS Monitoring and Operations

Remote Process Injection for Debugging

The new dcos task exec command allows you to remotely execute a process inside the container of a deployed Mesos task, providing the following features.

  • An optional --interactive flag for interactive sessions.
  • Attach to a remote pseudoterminal (aka PTY) inside a container via the optional --tty flag.
  • Combine the --interactive and --tty flags to launch an interactive bash session or to run top and see the resource usage of your container in real time.

For more information, see the documentation for the debugging documentation.


Stream task and system logs to journald by setting the mesos_container_log_sink install-time parameter to journald or journald+logrotate. This allows you to:

  • Include task metadata like container ID in your queries to more easily locate the logs that you want.
  • Use new DC/OS CLI commands dcos node log and dcos task log DC/OS CLI commands to query the logs. You can also make requests directly against the new Logging API.
  • Set up log aggregation solutions such as Logstash to get logs into their aggregated storage solutions.

For more information, see the documentation.


  • Node-level HTTP API that returns metrics from frameworks, cgroup allocations per container, and host level metrics such as load and memory allocation.
  • StatsD endpoint in every container for forwarding metrics to the DC/OS metrics service. This service is what exposes the HTTP API.
  • Any metric sent to STATSD_UDP_HOST/PORT is available in the HTTP API /container/<container_id>/app endpoint.

For more information, see the documentation.

Tool for Troubleshooting Service Deployment Failures

  • The new service deployment troubleshooting tool allows you to find out why your applications aren’t starting from the GUI and CLI.

    Service deploy GUI

Improved GUI

  • New look and feel and improved navigation.

    New GUI

  • Usability improvements to the service create workflow.

    Improved GUI

Networking Services

  • CNI support for 3rd party CNI plugins.
  • Performance improvements across all networking features.

Other Improvements

DC/OS Internals

  • Update DC/OS internal JDK to 8u112 for security fixes.
  • Update DC/OS internal Python from 3.4 to 3.5.
  • The dcos_generate_config.sh --aws-cloudformation command will now determine the region of the s3 bucket automatically, preventing region mistakes.
  • Added the dcos_add_user.py script, which you can use to add or invites users to a DC/OS cluster from the command line. For more information, see the documentation.
  • Added dcos-shell which activates the DC/OS environment for running other DC/OS command line tools.

Expanded OS Support

Expanded Docker Engine Support

  • Docker 1.12 and 1.13 are now supported. Docker 1.13 is the default version.


Improved upgrade tooling and experience for on-premise installations. Upgrades now use internal DC/OS APIs to ensure nodes can be upgraded with minimal disruption to running DC/OS services on a node. The upgrade procedure has also been simplified to improve user experience.

For more information, see the documentation.

Known Issues and Limitations

  • DCOS_OSS-691 - DNS becomes briefly unavailable during DC/OS version upgrades.
  • DCOS-14005 - Marathon-LB does not support pods.
  • DCOS-14021 - Task logging to journald disabled by default, so task logs will continue to be written to their sandboxes, and logrotated out. The dcos task log command will work as it did before.
  • DCOS-14047 - Marathon is killed during upgrades.
  • DCOS-14433 - The Universal container runtime does not support Azure cloud with Ubuntu.
  • DCOS-OSS-743 - If you are using Docker 1.13 on CentOS 7.3, the custom CLI installation method fails while installing prerequisites (--install-prereqs).
  • MARATHON-1713 - Volumes do not persist.
  • Marathon-7133 - Marathon application history is lost after Marathon restart.