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diff --git a/specs/mesos-deployment.rst b/specs/mesos-deployment.rst deleted file mode 100644 index 741758b67..000000000 --- a/specs/mesos-deployment.rst +++ /dev/null @@ -1,188 +0,0 @@ -============================== -Deploy Kolla images with Mesos -============================== - -https://blueprints.launchpad.net/kolla/+spec/mesos - -Kolla deploys the containers using Ansible, however this is just one -way to deploy the containers. For example TripleO deploys Kolla -containers using Heat in-guest agents. - -This specification defines the support for deploying Kolla containers -using Mesos and Marathon. - -What is Mesos? -From (http://mesos.apache.org/) Mesos "provides efficient resource -isolation and sharing across distributed applications, or frameworks". -The software enables resource sharing in a fine-grained manner, -improving cluster utilization. - -What is Marathon? -From (https://mesosphere.github.io/marathon/): -"A cluster-wide init and control system for services in cgroups or -Docker containers". - -Adding Mesos/Marathon support to Kolla will enable those interested in -deploying OpenStack with Mesos to contribute to the Kolla community -in a more direct way. - -Problem description -=================== - -The current deployment (Ansible) is done somewhat serially, meaning -that some services depend on others, and the deployment is controlled -by the command line (a user). In addition to deployment, Mesos/Marathon -provides the following features that will eventually be used: - -- life-cycle management: like service monitoring, restart, scaling - and rolling\restarts\upgrades -- constraints [1]: the Marathon scheduler will be used to more - effectively place containers (esp. during scaling/recovery) -- integration with core infrastructure services like DNS, Load - Balancing, Service Discovery and Service components. - -In order to reuse a large amount of functionality, it would be best -to use an existing framework that provides a proven stable and -mature solution. -Given that Mesos/Marathon is used and tested at scale by many large -companies, it will give operators the confidence to adopt -OpenStack to meet any scaling requirements they need. - -Marathon [2] will be used to manage the containers. Marathon is a -framework that runs on top of Mesos and it is for long running -services. - -Part of this change is to start all the containers at the same time -(in parallel) so that there are as few dependencies from the -deployment tool’s point of view. This should enable a couple of things: -- faster initial deployment -- reduce unnecessary restarts during upgrades -- make each container more self sufficient - -Proposed change -=============== - -- Add a deployment specific git repo (kolla-mesos) to contain the - Mesos/Marathon specific deployment code and boot strapping. -- Enhance Kolla container API (config.json) to permit loading - of custom startup script while maintaining immutability with copy_once. -- Implement an all in one (AIO) basic OpenStack -- Implement a separate controller/compute setup similar to the Ansible one. -- Throughout add docs to assist users and contributors/reviewers. - -Bootstrapping: --------------- - -At first, Mesos/Marathon/Zookeeper bootstrapping will be done by -setting up docker container. Later, bootstrapping will be handled by Ironic/PXE -(the aim is to be practical and do what is easiest for the AIO). - -Dependancy management ---------------------- - -Instead of the serialising the dependant steps, each container is -started and only actually starts the service if the requirements are -fulfilled. - -These dependencies will come in the form of: - -- service discovery (service X needs service Y running) - Note: that Marathon DNS and LB can be self-configured based on service - registry information. - To achieve this the container also needs to register itself once - it has started. -- checking to see if service configuration is complete - (has keystone got the service user that is required, is the DB - schema complete, etc..) - Use Zookeeper to watch for these configuration steps. - -One time tasks --------------- -Ansible runs a number of scripts to setup the database, keystone etc. -These can be run as a Mesos Executor (command line run in the -container of choice). - -Security impact ---------------- - -Mesos and Marathon are mature products used by various companies in -production. The central configuration storage will require careful -security risk assessment. The deployed OpenStack’s security should not -be affected by the deployment tool. - -Performance Impact ------------------- - -Given that the Mesos slaves are distributed and all containers will be -started in parallel, the deployment *may* be faster, though this is -not the main focus. - -Alternatives ------------- - -Kubernetes was evaluated by the Kolla team 6 months ago and found to -not work at that time as it did not support net=host and pid=host -features of docker. Since then it has developed these features, if -Mesos/Marathon fails to produce results, then going back to kubernetes -is an option. However at the time of writing this Mesos/Marathon was -deemed to be more mature and stable. - -Implementation -============== - -Primary Assignee(s) ------------ - Angus Salkeld (asalkeld) - Kirill Proskurin (kproskurin) - Michal Rostecki (nihilifer) - -Other contributor(s): - Harm Weites (harmw) - Jeff Peeler (jpeeler) - Michal Jastrzebski (inc0) - Sam Yaple (SamYaple) - Steven Dake (sdake) - <Please add your name here if you are getting involved in kolla-mesos> - -Milestones ----------- - -Target Milestone for completion: - mitaka - -Work Items ----------- -1. Allow a custom startup script to run (change in Kolla) -2. Add startup scripts to kolla-mesos to read config from zookeeper - instead of bindmounted directory. Propose oslo.config changes to - use this method (oslo work done in parallel, initially this will be - done in the startup script). -3. Add startup scripts for service discovery so that services only - start once their needs are fulfilled. - a. register a service once a service is running - b. wait for dependent services if they are needed before starting - a service. - c. DNS and LB self-configuration based on service registry information -5. Add bootstrapping code to install Marathon, Zookeeper, - Mesos master and slave. -6. Add calls to to marathon to deploy containers. -7. Add support for kolla-mesos to kolla-cli. - -Testing -======= - -Functional tests will be implemented in the OpenStack check/gating system to -automatically check that the Mesos/Marathon deployment works for an AIO environment. - -Documentation Impact -==================== -A quick start guide will be written to explain how to deploy. -A develop guide will be written on how to contribute and how the deployment works. - -References -========== - -- [1] https://mesosphere.github.io/marathon/docs/constraints.html -- [2] https://mesosphere.github.io/marathon/ -- http://radar.oreilly.com/2015/10/swarm-v-fleet-v-kubernetes-v-mesos.html -- https://www.wehkamplabs.com/blog/2015/10/15/applying-consul-within-the-blaze-microservices-platform/ |