A Technical I.T./DevOps Blog
Problem scenario
You want to install Composer (a dependency manager for PHP) on your Debian/Ubuntu Linux server. What do you do?
Solution
sudo apt -y update
sudo apt -y install php-cli unzip
cd ~
sudo curl -sS https://getcomposer.org/installer -o composer-setup.php
HASH=curl -sS https://composer.github.io/installer.sig
echo $HASH
php -r “if (hash_file(‘SHA384’,
…
Continue reading “How Do You Install Composer on Debian/Ubuntu Linux?”
Problem scenario
You have a heterogeneous enterprise network of servers. You want your Linux machines to communicate and transfer files with your Windows machines. You do not want to use Active Directory. What do you do?
Solution
1. Install Cygwin on the Windows server if it has not been set up already. If you need assistance with this, see this posting.
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Continue reading “How Do You Set up SSH on a Windows 2016 Server with Cygwin?”
Problem scenario
You have a Kubernetes cluster in AWS. You have the AWS CLI installed. How do you find the URL for the Kubernetes cluster?
Solution
1. Run this command: aws eks list-clusters
2. Run this command: aws eks describe-cluster foobar # where “foobar” was name determined in above command
…
Problem scenario
You want to determine what VPC a given AWS server is in. How do you find this out?
Solution
Prerequisite
You must have the AWS CLI installed and configured with a user that has the ability to view EC-2 databases (e.g., an administrator of your AWS account). If you need assistance, see this posting.
Procedure
Run this command: aws rds describe-db-instances | grep -i vpc
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Continue reading “How Do You Find what VPC an EC-2 Instance Is In?”
Problem scenario
You want to make and test Ansible roles, and therefore you want to use Molecule. You are using RHEL version 8.x. You want to use Python 3 and Molecule. What should you do?
Solution
Prerequisites
i. You should install Docker. If you need assistance, see this posting.
ii. You should install these packages before hand:
sudo yum -y install gcc python3-devel
sudo dnf install -y redhat-rpm-config
Procedures
1.
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Continue reading “How Do You Install Molecule on RHEL v. 8.x with Python 3?”
Problem scenario
You want to know if a MapReduce job succeeded. What do you do?
Solution
Run one or both of these pairs of commands:
hadoop job -list all
hadoop job -list all | grep SUCCEEDED
mapred job -list all
mapred job -list all | grep SUCCEEDED
…
Continue reading “How Do You Know if a MapReduce Job Succeeded?”
Problem scenario
You want to be sure that a given Aurora database is in a specific VPC. How do you determine what VPC it is in?
Solution
Prerequisite
You must have the AWS CLI installed and configured with a user that has the ability to view Aurora databases (e.g., an administrator of your AWS account). If you need assistance,
…
Continue reading “How Do You Find what VPC an Aurora Database Is In?”
Problem scenario
Your Groovy code has a section like this:
class Example {
static void main(String[] args) {
…
But this section above is not executing when you run your Groovy program. There are no errors however. How do you get it to execute?
Possible Solution #1
Remove lines of code (or statements) that are outside the “class Example {…”
Possible Solution #2
See this posting: How Do You Invoke a Class in a Groovy Program?
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Continue reading “How Do You Invoke the main Section of a Groovy Program?”
Problem scenario
You want to manage your Amazon Kubernetes (i.e., EKS) cluster. You have installed the AWS CLI version on a Linux server, and you want to use the update-config or update-kubeconfig command.
But when you try you see messages like “error argument command: Invalid choice…” or “update-config: command not found”. You could not readily find an example. What should you do?
Solution
Background
The command is update-kubeconfig,
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Continue reading “How Do You Use the aws update-kubeconfig Command?”
Problem scenario
You want to monitor network traffic on an EC-2 server’s NICs. You are not sure what to look for or what a baseline should look like. What do you do?
Solution
1. Install dstat. With a CentOS/RHEL/Fedora server, run this: sudo yum -y install dstat
2. Run this command: dstat -nt
3. With no network activity beyond the PuTTy session to the EC-2 server,
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Continue reading “How Do You Interpret the dstat Utility’s Results on a Linux Server in AWS?”