A Technical I.T./DevOps Blog
Question
Some programming languages adhere to a discipline known as being “strongly typed.” This attribute governs variable assignments. Is Python a strongly-typed language?
Answer
Technically, yes it is. Some interviewers for jobs involving Python may ask this question and expect you to say “no it is not.”
Detailed Explanation
In software development there are many people who have used Python and found its variables to be “dynamically typed” and not “statically typed.”
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Problem scenario
You are running a curl command. But you get this error “curl: (52) Empty reply from server.” What is the problem?
Possible solution #1
You are using curl with a port assignment in the URL (e.g., http://coolname.com:5077). Try a different port.
Possible solution #2 (This solution is only relevant if the URL endpoint is supported by a Docker container.)
The docker-compose.yml file could be configured incorrectly. It may refer to files with incorrect paths. You may need to change the docker-compose.yml file to refer to correct paths. An alternative solution would be to create the necessary files that the docker-compose.yml file needs and the related subdirectories that the file is looking for. Your “docker-compose up” command may work with no errors. But the references to the URL path may produce the “Empty reply from server” if the docker-compose.yml file refers to directory paths (e.g., for nginx listening on a specific port) in subdirectories that do not exist.
Problem scenario
You run puppet agent -t -d and get this error:
“Error: /File[/var/lib/puppet/facts.d]: Failed to generate additional resources using ‘eval_generate’: SSL_connect returned=1”
What do you do?
Solution
This is more of a resolution rather than a diagnosis. The error should go away if you follow these steps.
On the Puppet agent node run these commands:
sudo cd /var/lib/puppet/ssl
sudo rm -rf *
sudo puppet agent -t -d
If you cannot find the ssl directory in the above location,
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Problem scenario
You need to install Java version 8 on a Windows 64 bit server. How do you do this with PowerShell?
Solution
1. Open PowerShell ISE as Administrator.
2. Run this script:
# This is a modified version of PowerShell code taken from this site:
# https://skarlso.github.io/2015/06/30/powershell-can-also-be-nice-or-installing-java-silently-and-waiting/
$JDK_VER=”1u151″
$JDK_FULL_VER=”8u151-b12″
$JDK_PATH=”1.8.0_151″
$source86 = “http://download.oracle.com/otn-pub/java/jdk/$JDK_FULL_VER/jdk-$JDK_VER-windows-i586.exe”
$source64 = “http://javadl.oracle.com/webapps/download/AutoDL?BundleId=230542_2f38c3b165be4555a1fa6e98c45e0808”
$destination86 = “C:\Program Files (x86)\$JDK_VER-x86.exe”
$destination64 = “C:\Program Files (x86)\$JDK_VER-x64.exe”
$client = new-object System.Net.WebClient
$cookie = “oraclelicense=accept-securebackup-cookie”
$client.Headers.Add([System.Net.HttpRequestHeader]::Cookie,
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Continue reading “How Do You Install Java Version 8 on a Windows 64 Bit Server with PowerShell?”
Problem scenarios
One, or both, of the following apply to your situation:
Problem scenario #1
How do you use AWS (the SNS component) to set up an email alert to be notified of a server going down?
Problem scenario #2
You want to use Amazon Route 53 to see how this component works. You do not want to register a domain name.
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Problem scenario
You are trying to install Snort or some other program that requires hwloc. You want to see if hwloc is installed. If it is installed, you would like to know which version it is. How do you find out if it is installed and the version (if it is installed)?
Solution
You could type “hwloc-” and then press the Tab key two times.
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Problem scenario
You created a tripwire keyfile. You perform a tripwire (e.g., twprint) command but you get this error:
### Error: Keyfile Read/Write error.
### /etc/tripwire/site.key
### Exiting…
What should you do?
Solution
Use sudo before the tripwire command. This error can happen when the Linux user has insufficient permissions to perform the tripwire (e.g., twprint) command
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Continue reading “How Do You Use Tripwire Commands without the “Keyfile Read/Write error”?”
Problem scenario
You want to use the AWS CLI on an Ubuntu server. You want to rapidly create EC-2 servers or use S3. You want to be able to script AWS management commands for rapid provisioning etc. from an Ubuntu Linux server. What do you do to install AWS CLI on an Ubuntu Linux server?
Solution
This works on an Azure server, an AWS EC-2 instance,
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Continue reading “How Do You Install the AWS CLI on an Ubuntu Server?”
Problem scenario
You want to prepare for WildFly Swarm to run Java EE programs. You want to deploy Red Hat’s WildFly application server in a Docker container. You are running a Linux server. What do you do?
Solution
Background
The regular JBoss Application server was renamed to Wildfly. Do not confuse the JBoss application server with the JBoss web server.
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Continue reading “How Do You Deploy the WildFly Application Server in Docker?”
Problem scenario
“docker login” is challenging you for a username and password. But after you enter the credentials and press enter, it hangs. You are not logging into the Docker registry. What is wrong?
Solution
It may be surprising, but you can be challenged for a username and password when the Docker registry is turned off. If a firewall blocks a necessary port to the Docker registry or if the Docker registry’s server is off completely,
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