DevOps

Docker container using Apache Mesos and Marathon

Apache Mesos is an open source cluster manager developed at UC Berkeley. It provides resource isolation and sharing across distributed applications.

The figure shows the main components of Mesos. Mesos consists of a master daemon that manages slave daemons running on each cluster node. Mesos frameworks are applications that run on Mesos and run tasks on these slaves. Slaves are either physical or virtual machines, typically from the same provider.

mesos-architecture

Mesos uses a two-level scheduling mechanism where resource offers are made to frameworks. The Mesos master node decides how many resources to offer each framework, while each framework determines the resources it accepts and what application to execute on those resources.

Marathon is a container orchestration platform running on Mesos. Multiple container formats are supported and Docker is certainly the most common one!

This blog will show how to setup Mesos, Marathon, and run a simple Docker image. This setup is only for the brave of heart. I’m always interested in looking under the hood and that’s what motivated this post. But a future post will show a more seamless install.

Let’s get started!

Configure CentOS VM

Download CentOS and configure the VM as shown:

centos-7.1-install

Install Components

Install the different components required for this setup.

  • Configure Mesos repo:
[arun@arun-centos ~]$ sudo rpm -Uvh http://repos.mesosphere.com/el/7/noarch/RPMS/mesosphere-el-repo-7-1.noarch.rpm
 
We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:
 
    #1) Respect the privacy of others.
    #2) Think before you type.
    #3) With great power comes great responsibility.
 
[sudo] password for arun:
Retrieving http://repos.mesosphere.com/el/7/noarch/RPMS/mesosphere-el-repo-7-1.noarch.rpm
warning: /var/tmp/rpm-tmp.9ssCDQ: Header V4 RSA/SHA1 Signature, key ID e56151bf: NOKEY
Preparing...                          ################################# [100%]
Updating / installing...
   1:mesosphere-el-repo-7-1           ################################# [100%]
  • Install Mesos and Marathon:
[arun@arun-centos ~]$ sudo yum -y install mesos marathon
Loaded plugins: fastestmirror, langpacks
base                                                     | 3.6 kB     00:00
extras                                                   | 3.4 kB     00:00
mesosphere                                               | 2.9 kB     00:00
mesosphere-noarch                                        | 2.9 kB     00:00
updates                                                  | 3.4 kB     00:00
(1/6): base/7/x86_64/group_gz                              | 155 kB   00:00
(2/6): extras/7/x86_64/primary_db                          | 117 kB   00:00
(3/6): mesosphere-noarch/primary_db                        | 2.5 kB   00:00
(4/6): mesosphere/x86_64/primary_db                        |  27 kB   00:00
(5/6): base/7/x86_64/primary_db                            | 5.3 MB   00:01
(6/6): updates/7/x86_64/primary_db                         | 4.1 MB   00:02
Determining fastest mirrors
 * base: mirror.supremebytes.com
 * extras: centos.den.host-engine.com
 * updates: mirror.hmc.edu
Resolving Dependencies
--> Running transaction check
---> Package marathon.x86_64 0:1.1.1-1.0.472.el7 will be installed
---> Package mesos.x86_64 0:0.28.1-2.0.20.centos701406 will be installed
--> Processing Dependency: subversion for package: mesos-0.28.1-2.0.20.centos701406.x86_64
--> Running transaction check
---> Package subversion.x86_64 0:1.7.14-10.el7 will be installed
--> Processing Dependency: subversion-libs(x86-64) = 1.7.14-10.el7 for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_wc-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_subr-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_repos-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_ra_svn-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_ra_neon-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_ra_local-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_ra-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_fs_util-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_fs_fs-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_fs_base-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_fs-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_diff-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_delta-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libsvn_client-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libaprutil-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Processing Dependency: libapr-1.so.0()(64bit) for package: subversion-1.7.14-10.el7.x86_64
--> Running transaction check
---> Package apr.x86_64 0:1.4.8-3.el7 will be installed
---> Package apr-util.x86_64 0:1.5.2-6.el7 will be installed
---> Package subversion-libs.x86_64 0:1.7.14-10.el7 will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
================================================================================
 Package            Arch      Version                       Repository     Size
================================================================================
Installing:
 marathon           x86_64    1.1.1-1.0.472.el7             mesosphere     64 M
 mesos              x86_64    0.28.1-2.0.20.centos701406    mesosphere     30 M
Installing for dependencies:
 apr                x86_64    1.4.8-3.el7                   base          103 k
 apr-util           x86_64    1.5.2-6.el7                   base           92 k
 subversion         x86_64    1.7.14-10.el7                 base          1.0 M
 subversion-libs    x86_64    1.7.14-10.el7                 base          921 k
 
Transaction Summary
================================================================================
Install  2 Packages (+4 Dependent packages)
 
Total download size: 96 M
Installed size: 168 M
Downloading packages:
warning: /var/cache/yum/x86_64/7/base/packages/apr-1.4.8-3.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
Public key for apr-1.4.8-3.el7.x86_64.rpm is not installed
(1/6): apr-1.4.8-3.el7.x86_64.rpm                          | 103 kB   00:00
(2/6): apr-util-1.5.2-6.el7.x86_64.rpm                     |  92 kB   00:00
(3/6): subversion-1.7.14-10.el7.x86_64.rpm                 | 1.0 MB   00:00
(4/6): subversion-libs-1.7.14-10.el7.x86_64.rpm            | 921 kB   00:00
warning: /var/cache/yum/x86_64/7/mesosphere/packages/mesos-0.28.1-2.0.20.centos701406.x86_64.rpm: Header V4 RSA/SHA1 Signature, key ID e56151bf: NOKEY
Public key for mesos-0.28.1-2.0.20.centos701406.x86_64.rpm is not installed
(5/6): mesos-0.28.1-2.0.20.centos701406.x86_64.rpm         |  30 MB   00:29
(6/6): marathon-1.1.1-1.0.472.el7.x86_64.rpm               |  64 MB   00:36
--------------------------------------------------------------------------------
Total                                              2.6 MB/s |  96 MB  00:36
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
Importing GPG key 0xF4A80EB5:
 Userid     : "CentOS-7 Key (CentOS 7 Official Signing Key) <security@centos.org>"
 Fingerprint: 6341 ab27 53d7 8a78 a7c2 7bb1 24c6 a8a7 f4a8 0eb5
 Package    : centos-release-7-2.1511.el7.centos.2.10.x86_64 (@anaconda)
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mesosphere
Importing GPG key 0xE56151BF:
 Userid     : "Mesosphere Archive Automatic Signing Key <support@mesosphere.io>"
 Fingerprint: 8102 6d00 04c4 4cf7 ef55 adf8 df7d 54cb e561 51bf
 Package    : mesosphere-el-repo-7-1.noarch (installed)
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-mesosphere
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : apr-1.4.8-3.el7.x86_64                                       1/6
  Installing : apr-util-1.5.2-6.el7.x86_64                                  2/6
  Installing : subversion-libs-1.7.14-10.el7.x86_64                         3/6
  Installing : subversion-1.7.14-10.el7.x86_64                              4/6
  Installing : mesos-0.28.1-2.0.20.centos701406.x86_64                      5/6
Created symlink from /etc/systemd/system/multi-user.target.wants/mesos-master.service to /usr/lib/systemd/system/mesos-master.service.
Created symlink from /etc/systemd/system/multi-user.target.wants/mesos-slave.service to /usr/lib/systemd/system/mesos-slave.service.
  Installing : marathon-1.1.1-1.0.472.el7.x86_64                            6/6
Created symlink from /etc/systemd/system/multi-user.target.wants/marathon.service to /usr/lib/systemd/system/marathon.service.
  Verifying  : apr-1.4.8-3.el7.x86_64                                       1/6
  Verifying  : subversion-1.7.14-10.el7.x86_64                              2/6
  Verifying  : apr-util-1.5.2-6.el7.x86_64                                  3/6
  Verifying  : mesos-0.28.1-2.0.20.centos701406.x86_64                      4/6
  Verifying  : marathon-1.1.1-1.0.472.el7.x86_64                            5/6
  Verifying  : subversion-libs-1.7.14-10.el7.x86_64                         6/6
 
Installed:
  marathon.x86_64 0:1.1.1-1.0.472.el7 mesos.x86_64 0:0.28.1-2.0.20.centos701406
 
Dependency Installed:
  apr.x86_64 0:1.4.8-3.el7             apr-util.x86_64 0:1.5.2-6.el7
  subversion.x86_64 0:1.7.14-10.el7    subversion-libs.x86_64 0:1.7.14-10.el7
 
Complete!
  • Install ZooKeeper:
[arun@arun-centos ~]$ sudo yum -y install mesosphere-zookeeper
[sudo] password for arun:
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirror.supremebytes.com
 * extras: centos.den.host-engine.com
 * updates: mirror.hmc.edu
Resolving Dependencies
--> Running transaction check
---> Package mesosphere-zookeeper.x86_64 0:3.4.6-0.1.20141204175332.centos7 will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
==================================================================================================
 Package                  Arch       Version                                 Repository      Size
==================================================================================================
Installing:
 mesosphere-zookeeper     x86_64     3.4.6-0.1.20141204175332.centos7        mesosphere     2.8 M
 
Transaction Summary
==================================================================================================
Install  1 Package
 
Total download size: 2.8 M
Installed size: 3.5 M
Downloading packages:
mesosphere-zookeeper-3.4.6-0.1.20141204175332.centos7.x86_64.rpm           | 2.8 MB  00:00:01
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : mesosphere-zookeeper-3.4.6-0.1.20141204175332.centos7.x86_64                   1/1
Created symlink from /etc/systemd/system/multi-user.target.wants/zookeeper.service to /usr/lib/systemd/system/zookeeper.service.
  Verifying  : mesosphere-zookeeper-3.4.6-0.1.20141204175332.centos7.x86_64                   1/1
 
Installed:
  mesosphere-zookeeper.x86_64 0:3.4.6-0.1.20141204175332.centos7
 
Complete!
  • Add Docker repo:
[arun@arun-centos ~]$ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/$releasever/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF
[sudo] password for arun:
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/$releasever/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
  • Install Docker:
[arun@localhost ~]$ sudo yum -y install docker-engine
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirror.scalabledns.com
 * extras: linux.mirrors.es.net
 * updates: mirrors.adams.net
Resolving Dependencies
--> Running transaction check
---> Package docker-engine.x86_64 0:1.11.1-1.el7.centos will be installed
--> Processing Dependency: docker-engine-selinux >= 1.11.1-1.el7.centos for package: docker-engine-1.11.1-1.el7.centos.x86_64
--> Running transaction check
---> Package docker-engine-selinux.noarch 0:1.11.1-1.el7.centos will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
====================================================================================================
 Package                       Arch           Version                      Repository          Size
====================================================================================================
Installing:
 docker-engine                 x86_64         1.11.1-1.el7.centos          dockerrepo          13 M
Installing for dependencies:
 docker-engine-selinux         noarch         1.11.1-1.el7.centos          dockerrepo          28 k
 
Transaction Summary
====================================================================================================
Install  1 Package (+1 Dependent package)
 
Total download size: 13 M
Installed size: 54 M
Downloading packages:
warning: /var/cache/yum/x86_64/7/dockerrepo/packages/docker-engine-selinux-1.11.1-1.el7.centos.noarch.rpm: Header V4 RSA/SHA512 Signature, key ID 2c52609d: NOKEY
Public key for docker-engine-selinux-1.11.1-1.el7.centos.noarch.rpm is not installed
(1/2): docker-engine-selinux-1.11.1-1.el7.centos.noarch.rpm                  |  28 kB  00:00:00
(2/2): docker-engine-1.11.1-1.el7.centos.x86_64.rpm                          |  13 MB  00:00:02
----------------------------------------------------------------------------------------------------
Total                                                               5.3 MB/s |  13 MB  00:00:02
Retrieving key from https://yum.dockerproject.org/gpg
Importing GPG key 0x2C52609D:
 Userid     : "Docker Release Tool (releasedocker) <docker@docker.com>"
 Fingerprint: 5811 8e89 f3a9 1289 7c07 0adb f762 2157 2c52 609d
 From       : https://yum.dockerproject.org/gpg
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : docker-engine-selinux-1.11.1-1.el7.centos.noarch                                 1/2
restorecon:  lstat(/var/lib/docker) failed:  No such file or directory
warning: %post(docker-engine-selinux-1.11.1-1.el7.centos.noarch) scriptlet failed, exit status 255
Non-fatal POSTIN scriptlet failure in rpm package docker-engine-selinux-1.11.1-1.el7.centos.noarch
  Installing : docker-engine-1.11.1-1.el7.centos.x86_64                                         2/2
  Verifying  : docker-engine-1.11.1-1.el7.centos.x86_64                                         1/2
  Verifying  : docker-engine-selinux-1.11.1-1.el7.centos.noarch                                 2/2
 
Installed:
  docker-engine.x86_64 0:1.11.1-1.el7.centos
 
Dependency Installed:
  docker-engine-selinux.noarch 0:1.11.1-1.el7.centos
 
Complete!

Configure Hostname/IP address Mapping

Edit /etc/hosts and create hostname and IP address mapping. Find IP address using ifconfig and choose the network interface enabled during CentOS installation.

Start Services

Start all the services

  • Start Docker:
[arun@arun-centos ~]$ sudo service docker start
Redirecting to /bin/systemctl start  docker.service
  • Start ZooKeeper:
sudo systemctl start zookeeper
  • Start Mesos master:
[arun@arun-centos ~]$ sudo service mesos-master start
Redirecting to /bin/systemctl start  mesos-master.service
  • Configure mesos and docker containerizers:
sudo sh -c "echo 'docker,mesos' > /etc/mesos-slave/containerizers"
  • Start Mesos slave:
[arun@arun-centos ~]$ sudo service mesos-slave start
Redirecting to /bin/systemctl start  mesos-slave.service
  • Start Marathon:
[arun@arun-centos ~]$ sudo service marathon start
Redirecting to /bin/systemctl start  marathon.service
[arun@arun-centos log]$ ps aux | grep meso
root      4511  0.1  0.7 3974136 58968 ?       Ssl  19:54   0:04 java -Dzookeeper.log.dir=. -Dzookeeper.root.logger=INFO,CONSOLE -cp /opt/mesosphere/zookeeper/bin/../build/classes:/opt/mesosphere/zookeeper/bin/../build/lib/*.jar:/opt/mesosphere/zookeeper/bin/../lib/slf4j-log4j12-1.6.1.jar:/opt/mesosphere/zookeeper/bin/../lib/slf4j-api-1.6.1.jar:/opt/mesosphere/zookeeper/bin/../lib/netty-3.7.0.Final.jar:/opt/mesosphere/zookeeper/bin/../lib/log4j-1.2.16.jar:/opt/mesosphere/zookeeper/bin/../lib/jline-0.9.94.jar:/opt/mesosphere/zookeeper/bin/../zookeeper-3.4.6.jar:/opt/mesosphere/zookeeper/bin/../src/java/lib/*.jar:/etc/zookeeper/conf: -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false org.apache.zookeeper.server.quorum.QuorumPeerMain /etc/zookeeper/conf/zoo.cfg
root     15786  0.0  0.2 754788 19596 ?        Ssl  20:43   0:00 /usr/sbin/mesos-slave --master=zk://localhost:2181/mesos --log_dir=/var/log/mesos
root     15792  0.0  0.0 107892   624 ?        S    20:43   0:00 logger -p user.info -t mesos-slave[15786]
root     15793  0.0  0.0 107892   700 ?        S    20:43   0:00 logger -p user.err -t mesos-slave[15786]
root     15837  1.9  3.0 2818056 239208 ?      Ssl  20:43   0:10 java -Djava.library.path=/usr/local/lib:/usr/lib:/usr/lib64 -Djava.util.logging.SimpleFormatter.format=%2$s%5$s%6$s%n -Xmx512m -cp /usr/bin/marathon mesosphere.marathon.Main --zk zk://localhost:2181/marathon --master zk://localhost:2181/mesos
root     15838  0.0  0.2 829028 22908 ?        Ssl  20:43   0:00 /usr/sbin/mesos-master --zk=zk://localhost:2181/mesos --port=5050 --log_dir=/var/log/mesos --quorum=1 --work_dir=/var/lib/mesos
root     15863  0.0  0.0 107892   620 ?        S    20:43   0:00 logger -p user.info -t mesos-master[15838]
root     15864  0.0  0.0 107892   696 ?        S    20:43   0:00 logger -p user.err -t mesos-master[15838]
arun     16931  0.0  0.0 112644   952 pts/0    R+   20:52   0:00 grep --color=auto meso
  • Check Mesos master:
[arun@arun-centos ~]$ systemctl status mesos-master
● mesos-master.service - Mesos Master
   Loaded: loaded (/usr/lib/systemd/system/mesos-master.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2016-05-04 19:42:24 EDT; 32min ago
 Main PID: 8499 (mesos-master)
   Memory: 14.6M
   CGroup: /system.slice/mesos-master.service
           ├─8499 /usr/sbin/mesos-master --zk=zk://localhost:2181/mesos --port=5050 --log_dir=/va...
           ├─8513 logger -p user.info -t mesos-master[8499]
           └─8514 logger -p user.err -t mesos-master[8499]
 
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.564679  8527 master.cpp:3104] Proc...
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.565058  8527 master.hpp:177] Ad...os)
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.565093  8527 master.cpp:3589] Laun...
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.577255  8527 master.cpp:4763] Stat...
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.577287  8527 master.cpp:4811] F...000
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.577325  8527 master.cpp:6421] U...ED)
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.587143  8527 master.cpp:3918] Proc...
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.587198  8527 master.cpp:6487] Remo...
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.726095  8527 master.cpp:5324] S...006
May 04 20:14:41 arun-centos mesos-master[8514]: I0504 20:14:41.728080  8527 master.cpp:3641] P...006
Hint: Some lines were ellipsized, use -l to show in full.
  • Check Mesos slave:
[arun@arun-centos ~]$ systemctl status mesos-slave
● mesos-slave.service - Mesos Slave
   Loaded: loaded (/usr/lib/systemd/system/mesos-slave.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2016-05-04 20:00:43 EDT; 12min ago
 Main PID: 9864 (mesos-slave)
   Memory: 57.5M
   CGroup: /system.slice/mesos-slave.service
           ├─9864 /usr/sbin/mesos-slave --master=zk://localhost:2181/mesos --log_dir=/var/log/mes...
           ├─9876 logger -p user.info -t mesos-slave[9864]
           └─9877 logger -p user.err -t mesos-slave[9864]
 
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.283629  9887 status_update_manag...000
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289118  9887 slave.cpp:3990] Cle...000
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289422  9887 slave.cpp:4078] Cle...000
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289459  9887 gc.cpp:55] Scheduling ...
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289489  9887 gc.cpp:55] Scheduli...ure
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289499  9887 gc.cpp:55] Scheduling ...
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289511  9887 gc.cpp:55] Scheduli...ure
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289520  9887 gc.cpp:55] Scheduli...ure
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289525  9887 gc.cpp:55] Scheduli...ure
May 04 20:13:26 arun-centos mesos-slave[9877]: I0504 20:13:26.289533  9887 status_update_manag...000
Hint: Some lines were ellipsized, use -l to show in full.
  • Check ZooKeeper:
[arun@arun-centos log]$ /opt/mesosphere/zookeeper/bin/zkCli.sh
Connecting to localhost:2181
log4j:WARN No appenders could be found for logger (org.apache.zookeeper.ZooKeeper).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Welcome to ZooKeeper!
JLine support is enabled
 
WATCHER::
 
WatchedEvent state:SyncConnected type:None path:null
[zk: localhost:2181(CONNECTED) 0] ls /mesos
[json.info_0000000001, log_replicas]

Deploy Docker application to Mesos

A simple Docker-based application is defined using the configuration file. Marathon runs on port 8080 and so the updated configuration file looks like:

{
  "id": "basic-3",
  "cmd": "python3 -m http.server $PORT0",
  "cpus": 0.5,
  "mem": 32.0,
  "container": {
    "type": "DOCKER",
    "docker": {
      "image": "python:3",
      "forcePullImage": true,
      "network": "BRIDGE",
      "portMappings": [
        { "containerPort": 0, "hostPort": 0 }
      ]
    }
  }
}

Deploy the application as:

curl -X POST http://127.0.0.1:8080/v2/apps -d @app.json -H "Content-type: application/json"

The application will take some time in order to download the image and then run the container. This setup is slightly sensitive and multiple runs of the application showed that the Docker image was not successfully downloaded all the times. In that case, the Docker image was manually downloaded using docker pull python:3 and then the application could be successfully deployed.

In our case, master and slave are running on the same machine, and so the list of Docker images and running containers can be easily seen:

[arun@localhost ~]$ sudo docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
python              3                   67b5207e5d3b        8 days ago          671.1 MB
[arun@localhost ~]$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                      NAMES
2ee42b120537        python:3            "/bin/sh -c 'python3 "   About an hour ago   Up About an hour    0.0.0.0:31669->31669/tcp   mesos-d03f6e61-063f-4cae-9c1b-3fc6d8384b3a-S0.b99d82f6-9bc1-4a6f-ae3b-53b7f5d06b95

The application is available at port 31669 and can be seen at http://127.0.0.1:31669 as:

mesos-marathon-app-output

Mesos UI (http://127.0.0.1:5050) shows:

marathon-ui-app-output

Marathon UI (http://127.0.0.1:8080) shows:

mesos-ui-app-output-1024x363

As you can see, this is quite an involving setup. A future blog post will show how to use DC/OS and set this up more seamlessly.

Further reading …

Mesos slack channel is awesome! Particularly I learned a lot about Mesos from @jgarcia.mesosphere, @akaplan.mesosphere, @harpreet.mesosphere, @graham.mesosphere. Thanks guys, keep up on engaging with the community!

Enjoy!

Arun Gupta

Arun is a technology enthusiast, avid runner, author of a best-selling book, globe trotter, a community guy, Java Champion, JavaOne Rockstar, JUG Leader, Minecraft Modder, Devoxx4Kids-er, and a Red Hatter.
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