Prerequisites for adding the Linux Container Build Box to create the Linux containers


Preferred operating systems

Operating System Version
Ubuntu 16+
RHEL 7.6+, 8.x
CentOS 7.5+

Hardware requirements

Resource CPU RAM /opt docker partition ( typically /var/lib/docker/ )
Requirement 4 cores 16 GB 100 GB 200 GB 
[ssh-user@Build Box ~]$ df -lh
Filesystem      Size  Used Avail Use%  Mounted on
/dev/sda1       440G   34G  406G   8%  /      <- "/opt is part of /" and "406GB > 100GB"

Tip : You have an option on the OmniDeq UI to delete the files copied at /opt partition once the docker container is successfully built. You can use this option to make sure that the required space is always available.

[ssh-user@Build Box ~]$ ls -ltr /opt
drwxr-xr-x  9 root         testdir  288 Sep 27  2016 X11    

"x" is required which ensures the execute permission.
"d" is required which ensures that it is a directory.

Privilege Access

The user account used for connection between OmniDeq/Host machine and Build Box ( 'ubuntu' for example ) must have privilege access.

Below line can be added to /etc/sudoers for allowing connecting user to communicate without password certain commands. Please update the path for system commands like env, md5sum, etc.

ubuntu ALL=(ALL) NOPASSWD: /usr/bin/env, /usr/bin/md5sum, /usr/bin/cp, /usr/bin/mv, /opt/.ch-tools/*/*, /usr/bin/docker, /usr/bin/echo, /usr/bin/cat, /usr/bin/base64, /usr/bin/mkdir, /usr/bin/chmod -R 775 /opt/.ch-tools, /bin/chmod -R 775 /opt/.ch-tools/data, /bin/chown -R ubuntu\: /home/ubuntu/.ch-*,/bin/chown -R ubuntu\: /opt/.ch-tools/*/*/*/*/*/*, /bin/chown -R ubuntu\: /opt/.ch-tools/*/*/*/*/*, /bin/chown -R ubuntu\: /opt/.ch-tools/*/*/*/*,/bin/chown -R ubuntu\: /opt/.ch-tools/*/*/*, /bin/chown -R ubuntu\: /opt/.ch-tools/*/*, /bin/chown -R ubuntu\: /opt/.ch-tools/*, /bin/chown -R ubuntu\: /opt/.ch-tools, /bin/chown -R ubuntu\: /opt/.ch-tools/data, /bin/chown ubuntu\: /home/ubuntu/.ch-*,/opt/.ch-tools/*/*/*/*/*/*/*/*, /bin/chmod -R 775 /opt/.ch-tools/*, /bin/chmod 755 /opt/.ch-tools/*/*

SSHD server

The ssh server (sshd) must be running on the Build Box. Verify it as follows on the Build Box.

[ssh-user@host ~]$ ps ax | grep <sshd or openssh or equivalent>

Connection Method

OmniDeq and Host machine authenticates with the Build Box using the following 2 methods over ssh,

The data transfer between Host machine and Build Box is over ssh using rsync.

Docker

Docker community edition version 18 or higher must be installed on Build Box. Verify it as follows on the Build Box.

[ssh-user@Build Box ~]$ docker version
Client: Docker Engine - Community
 Version:           19.03.1

If not, you can refer to Docker's Official Documentation.

For reference, visit the link to install the Docker.

Docker Overlay setting

'Native Overlay Diff' flag must be set as true for the images to be created properly. Verify it as follows on the Build Box.

docker info | grep Diff
Native Overlay Diff: true

If it is set as false, please run the following command as root and set it as true. Please note the docker deamon needs to be restarted for this to take effect (already included in the command)

modprobe -r overlay && modprobe overlay redirect_dir=on && systemctl restart docker

Disable SELinux

Make sure SELinux is disabled on the Build Box. To disable please follow the below command.

$ sed -i 's/^SELINUX=.*/SELINUX=disabled/g' /etc/sysconfig/selinux && cat /etc/sysconfig/selinux
$ setenforce 0
$ sestatus

RequireTTY

Disable requiretty for connecting user from remote machine to Build Box. If set, sudo will only run when the user is logged in to a real terminal and not via other means such as cron, cgi-bin or ssh scripts. Since OmniDeq connects to the build Box remotely without a real terminal, this flag must be disabled. This flag is off by default. Below line can be added to /etc/sudoers file.

Defaults:ubuntu    !requiretty

Base Container Images Availability

The application container images are built using the standard images (e.g Ubuntu, CentOS) as base. These base images are fetched from either the public/private docker repository over internet at run time or used from the locally available images on the build box. Please ensure that

  1. The public/private docker repository is accessible from Build Box to download the base container image at run time without any authentication.
  2. Or Pre-download the base container image on Build Box in case of public/private repository requires authentication.

Uploading Docker Containers To Container Repository

If the docker container images are to be uploaded to publc repository like ECR, DockerHub please make sure that the internet access is enabled between Build Box and container repository.

Uploading to AWS ECR

If the image is to be pushed to ECR, aws-cli should be installed. Install the aws cli version 1 using the Link. After successful installation verify it as follows on the Build Box.

[ssh-user@Build Box ~]$ sudo su -
[ssh-user@Build Box ~]$ aws --version
aws-cli/1.18.100 Python/2.7.17 Linux/4.18.0-193.el8.x86_64 botocore/1.17.23

Tip : If you cannot fetch the output of above command then, add the below line to "~/.bashrc" file and save it. It will get aws binary in the path.

export PATH=$PATH:$HOME/bin:/usr/local/bin

Tip : Please make sure that repository to which docker images are be pushed is already pre-created on AWS ECR.