[mesos] branch master updated: Added blog post for Mesos Mini.

[ji...@apache.org]

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The following commit(s) were added to refs/heads/master by this push:
     new 05a7caf  Added blog post for Mesos Mini.
05a7caf is described below

commit 05a7caf2de270eb01f7a13784f4b1e0ee333723f
Author: Jie Yu <yu...@gmail.com>
AuthorDate: Sun Nov 18 21:44:50 2018 -0800

    Added blog post for Mesos Mini.
    
    Review: https://reviews.apache.org/r/69377/
---
 site/source/blog/2018-11-19-mesos-mini.md | 157 ++++++++++++++++++++++++++++++
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+---
+layout: post
+title: Run Mesos Locally with Mesos Mini Docker Container
+published: true
+post_author:
+  display_name: Jie Yu
+  twitter: jie_yu
+tags: Docker
+---
+
+[Mesos Mini](https://hub.docker.com/r/mesos/mesos-mini/) is a Docker image maintained by the Apache Mesos community.
+It allows you to test Mesos locally with a simple `docker run`.
+
+# Why Mesos Mini
+
+Being able to spin up a local Mesos cluster in Docker can greatly simplify the work in the following scenarios:
+
+* *Demo*: Imagine doing a live demo with Mesos in a conference with unstable Wifi.
+* *Framework development*: Write end-to-end integration tests for your framework with a local Mesos cluster in a Docker container.
+  This can be easily automated in your test suite.
+* *Test new Mesos features*: Test new features from Mesos that haven't been released yet.
+  You might be able to do that by building Mesos from the source code, but most framework developers do not know how to do it, and it is slow.
+
+The idea is similar to [minikube](https://github.com/kubernetes/minikube) or [minimesos](https://github.com/ContainerSolutions/minimesos).
+
+However, [minimesos](https://github.com/ContainerSolutions/minimesos) is no longer maintained.
+As a result, Apache Mesos community decides to maintain a solution in Mesos repository to simplify CI integrations.
+
+# Get started
+
+Make sure [Docker](https://docs.docker.com/install/) is installed.
+We have tested on both Linux and MacOS.
+
+To create a local Mesos cluster, simply do a `docker run`:
+
+```bash
+$ docker run --rm --privileged -p 5050:5050 -p 5051:5051 -p 8080:8080 mesos/mesos-mini
+```
+
+It will launch one Mesos master, one Mesos agent, and one example framework (Marathon) in the Docker container.
+
+You should be able to access Mesos master UI at `http://localhost:5050`.
+Similarly, you can access Mesos agent at `http://localhost:5051`.
+Marathon UI can be accessed at `http://localhost:8080`.
+
+You should be able to launch containers in the local Mesos cluster using Marathon like the following:
+
+```bash
+$ cat app.json
+{
+  "id": "test",
+  "cmd": "sleep 1000",
+  "cpus": 1,
+  "mem": 128,
+  "disk": 0,
+  "instances": 1,
+  "container": {
+    "docker": {
+      "image": "alpine"
+    },
+    "type": "DOCKER"
+  },
+  "networks": [
+    {
+      "mode": "host"
+    }
+  ]
+}
+$ curl -X POST -d @app.json -H "Content-type: application/json" http://localhost:8080/v2/apps
+```
+
+To stop the local Mesos cluster, please use `docker stop`.
+All artifacts associated with the local Mesos cluster will be cleaned up when the Docker container stops.
+
+The following Docker image tags are maintained:
+
+* `master`: The latest master branch HEAD.
+* `<RELEASE_BRANCH>`: The latest release branch HEAD (e.g., `1.7.x`).
+* `master-<DATE>`: The snapshot builds for master branch (e.g., `master-2018-11-19`).
+* `<RELEASE_BRANCH>-<DATE>`: The snapshot builds for release branch (e.g., `1.7.x-2018-11-19`).
+
+Note that there is no support for release branches earlier than `1.7.x`.
+All future release branches will be supported.
+
+# How is it done?
+
+## Manage multiple services
+
+We use `systemd` to manage multiple daemons in the Mesos Mini Docker container.
+As a result, you can use the following command to restart the Mesos master in the Mesos Mini Docker container:
+
+```bash
+$ docker exec <CONTAINER_ID> systemctl restart mesos-master
+```
+
+Similarly, you can use that to restart other services (e.g., Mesos agent or Marathon).
+This is very useful for those end-to-end integration tests that want to simulate Mesos master failover.
+
+## Docker Containerizer
+
+One of the goals of Mesos Mini is to mimic production settings as much as possible.
+
+To allow frameworks to launch Docker containers, we embed a Docker Daemon (i.e., Docker in Docker) in the Mesos Mini Docker container.
+For instance, to view all Docker containers in the Mesos cluster, use the following command on your host:
+
+```bash
+$ docker exec <CONTAINER_ID> docker ps
+```
+
+The cgroup root for the embedded Docker Daemon has been configured so that the cgroups for the nested Docker containers are properly nested within the Mesos Mini Docker container.
+This ensures that no cgroups traces will be left in the system when the Mesos Mini Docker container finishes.
+
+## Mesos Containerizer (UCR)
+
+For Mesos Containerizer (UCR), we turn on most of the [isolators](https://github.com/apache/mesos/docs/mesos-containerizer.md) that are typically turned on in production environments.
+Similar to Docker daemon, we need to do a few tweaking on cgroups in Mesos Mini Docker container to make sure it does not leave any traces when Mesos Mini Docker container terminates.
+
+For each cgroup subsystem, Docker does a bind mount from the current cgroup to the root of the cgroup subsystem.
+For instance:
+
+```bash
+/sys/fs/cgroup/memory/docker/<cid> -> /sys/fs/cgroup/memory
+```
+
+This will confuse Mesos agent and UCR because it relies on proc file `/proc/<pid>/cgroup` to determine the cgroups of a given process, and this proc file is not affected by the bind mount of the cgroups.
+
+To workaround that, we perform the following steps for each cgroup subsystems when bootstrapping the Mesos Mini Docker container to recreates the cgroups layout as if it were on the host.
+
+```bash
+$ mkdir -p /sys/fs/cgroup/memory/docker/<cid>
+$ mount --bind /sys/fs/cgroup/memory /sys/fs/cgroup/memory/docker/<cid>
+```
+
+And then set Mesos agent `--cgroups_root` flag to `docker/<cid>`.
+
+# Maintenance
+
+The [build scripts](https://github.com/apache/mesos/tree/master/support/mesos-mini) for Mesos Mini is hosted in Mesos repository.
+The [Mesos Docker Mini Jenkins CI](https://builds.apache.org/view/M-R/view/Mesos/job/Docker/job/Mini/) has been setup to automatically push daily snapshot builds to Docker hub for supported release branches as well as the master branch.
+
+For any bug fix or new features, please follow the [Apache Mesos contribution guide](http://mesos.apache.org/community/#contribute-a-patch).
+
+## Mesos CentOS Docker Image
+
+In some scenarios, some users might prefer having a Docker image that only has Mesos installed.
+To enable that, we also built a `mesos/mesos-centos` Docker image.
+The tags are similar to those of Mesos Mini.
+In fact, `mesos/mesos-mini` uses `mesos/mesos-centos` as its base image.
+
+The [build scripts](https://github.com/apache/mesos/tree/master/support/packaging/centos/build-docker-centos.sh) for Mesos CentOS Docker image is also hosted in Mesos repository.
+The [Mesos Docker CentOS Jenkins CI](https://builds.apache.org/view/M-R/view/Mesos/job/Docker/job/CentOS/) has been setup to automatically push daily snapshot builds to Docker hub for supported release branches as well as the master branch.
+
+# Current limitations
+
+* Only one Mesos agent can be launched in the Mesos Mini Docker container.
+* Marathon uses in-memory storage instead of ZK.
+* SSL is not enabled.