A Technical I.T./DevOps Blog
Problem scenario
You want to remove Docker from your Ubuntu server. You tried this command:
sudo apt-get remove docker
But you see this:
“
…
Active: failed (Result: exit-code) since Sun 2017-08-06 21:59:11 EDT; 11ms ago
Docs: https://docs.docker.com
Process: 21981 ExecStart=/usr/bin/dockerd -H fd:// $DOCKER_OPTS (code=exited, status=1/FAILURE)
Main PID: 21981 (code=exited, status=1/FAILURE)
Memory: 14.0M
…
Problem scenario
You have Docker installed. When running “docker ps” you get this error: “An error occurred trying to connect: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.24/containers/json: read unix @->/var/run/docker.sock: read: connection reset by peer”
How do you fix this error so you can use Docker?
Solution
Just because Docker was installed does not mean that the kernel of your OS is supported. Docker may not work despite being installed.
…
Problem scenario
You want your website to perform well. By default Nginx’s load balancing system uses the round-robin technique. You want available yet under-utilized web servers to handle inbound connection requests (aka someone using a web browser to go to a web page). Individual users can put a disparate load on a given Nginx instance. Some website users will spend a significant amount of time on a web page. Others will invoke various application features that will require more resources than others.
…
Problem scenario
You want to install Docker on an AWS instance of Ubuntu. But you do not know how. How can you quickly do this?
Solution
Run these two commands:
sudo apt-get -y update
sudo apt -y install docker.io
An alternative set of directions is here. For a variety of different directions for all different types of Linux,
…
Continue reading “How Do You Install Docker on an AWS Instance of Ubuntu?”
Problem scenario
You want to deploy Docker to Ubuntu Linux using Puppet. How do you write a manifest to install Docker an Ubuntu server?
Solution
This solution demonstrates transferring a file with Puppet.
1. Install Puppet master on an Ubuntu Server. See this link if you want directions.
2. Install Puppet agent on a different Ubuntu server. See this
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Continue reading “How Do You Deploy Docker to Ubuntu Linux Servers Using Puppet?”
Problem scenario
You want to use Puppet to deploy Docker to a RHEL server in AWS. How do you do this?
Solution
Warning: This may not work for Puppet versions 5 or higher. It should work for Puppet version 4 or lower. This solution is not a best practice. It is quick way to deploy a version of Docker made for CentOS to RHEL instances.
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Continue reading “How Do You Deploy Docker to RedHat Linux Servers Using Puppet?”
Problem scenario
You are using a Linux SUSE server in AWS. You want to install Vagrant. What do you do?
Solution
Run these commands:
cd /tmp
sudo curl https://releases.hashicorp.com/vagrant/1.8.1/vagrant_1.8.1_x86_64.rpm > vagrant_1.8.1_x86_64.rpm
sudo zypper -n install vagrant_1.8.1_x86_64.rpm
To verify the installation, run this command: vagrant version
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Continue reading “How Do You Install Vagrant on an AWS Instance of SUSE?”
Problem scenario
You are using a RHEL (RedHat Enterprise Linux) server in AWS. You want to install Vagrant. What do you do?
Solution
Assume the root user by issuing this command: sudo su –
Run these commands:
yum -y install wget
cd /tmp
wget https://releases.hashicorp.com/vagrant/1.8.1/vagrant_1.8.1_x86_64.rpm
yum -y localinstall vagrant_1.8.1_x86_64.rpm
To verify the installation, run this command: vagrant version
Alternative Solution
If you do not want to install wget and curl commands will work for retrieving https locations,
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Continue reading “How Do You Install Vagrant on an AWS Instance of RedHat Linux?”
Problem scenario
You want to install Docker on Linux. How do you determine if the VM or physical server with Linux meets the minimum requirements for installing Docker?
Solution
Run this script:
#!/bin/bash
# Written by continualintegration.com
echo “This will test if your Linux server is ready for Docker.”
i=0;
os=$(uname -m | grep -i x)
if [ -z “$os” ];
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Continue reading “How Do You Know If Your Linux Server Can Support a Docker Installation?”
Problem scenario
You want to install Docker, but you want to be sure that the kernel is high enough to be supported.
Solution
The minimum kernel version is stated on Docker’s website. As the spring time of 2017, run this script to find out if your kernel version is high enough:
a=$(uname -r)
b=$(echo $a | awk -F
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Continue reading “How Do You Know If Your Linux Kernel Meets the Minimum Requirements for Docker?”