A Technical I.T./DevOps Blog
Problem scenario
You run an ansible-playbook command, but you get “ERROR! the field hosts is required but was not set”. What should you do?
Solution
Find the hyphens beneath the top “- name” stanza. Eliminate them. For example, if your playbook looks like this:
– name: Foobar
hosts: localhost
– vars:
goodone: “blahblah”
-tasks:
…
Make it look like this:
– name: Foobar
hosts: localhost
vars:
goodone: “blahblah”
tasks:
…
Now re-run it.
…
Problem scenario
You try to run a playbook. But you get a message like this: ‘fatal: … “AnsibleUndefinedVariable” ‘hadoop_env’ is undefined’. What should you do?
Root cause: a variable you defined (e.g., in a playbook or role) is not getting assigned when you run the playbook.
Possible solution #1
Find the vars directory or create it.
…
Continue reading “How Do You Troubleshoot the Ansible Error ‘”hadoop_env” is undefined’?”
Problem scenario
When in virtualenv you try to run a Molecule command. But you get this message:
ERROR: Unable to contact the Docker daemon. Please refer to https://docs.docker.com/config/daemon/ for managing the daemon
What should you do?
Solution
1. Exit virtualenv. Run this command: deactivate
2. Go back into virtualenv (e.g., run a command like this source my_env/bin/activate).
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Problem scenario
You are running a manifest and you get this error:
Error: Failed to apply catalog: Parameter mode failed on File[/opt/hadoop/hadoop-2.2.0.tar.gz]: The file mode specification must be a string, not ‘Integer’ at /etc/puppetlabs/code/environments/production/modules/hadoop/manifests/init.pp:55
What is wrong?
Solution
Go to the Puppet Master server and open the file in the error. (The error provides the full directory path.) Go to the line number that the error message specifies.
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Problem scenario
You have Puppet agent and Puppet Master set up and configured to work together. You are are running open source Puppet 5.x on Ubuntu servers in AWS. You want to install Java on the Puppet agent nodes. You tried to use the Java module.
On the Puppet Master server, you ran this: puppet module install puppetlabs-java –version 2.2.0
This is your site.pp file:
class { ‘java’ :
package =’java-1.8.0-openjdk-devel’, …
Continue reading “How Do You Create a Puppet Manifest to Install Java?”
Problem scenario
You run puppet agent but you get this error:
Error: Could not request certificate: Failed to open TCP connection to puppetmaster.domain.com:8140 (Connection refused – connect(2) for “puppetmaster.domain.com” port 8140)
What do you do?
Solution
Ensure port 8140 is open. Install nmap on a server, and run this command:
nmap -p 8140 puppetmaster.domain.com
If you see this
PORT STATE SERVICE
8140/tcp closed unknown
Then the Puppet Master service is not running.
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Problem scenario
You run the Puppet agent on a server but you receive this error:
Error: Could not retrieve catalog from remote server: Error 500 on SERVER: Server Error: Could not find node statement with name ‘default’ or ‘ip-172-31-20-105.us-east-2.compute.internal, ip-172-31-20-105.us-east-2.compute, ip-172-31-20-105.us-east-2, ip-172-31-20-105’ on node ip-172-31-20-105.us-east-2.compute.internal
Warning: Not using cache on failed catalog
Error: Could not retrieve catalog; skipping run
What should you do?
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Problem scenario
You want to run an Ansible playbook to push configuration changes down (e.g., transfer files to managed nodes). How do you do this?
Solution
Prerequisites
This assumes that you have set up Ansible. If you need directions for deploying an Ansible control server, see this posting. If you need directions for deploying a managed node after the central Ansible server has been set up,
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Problem scenario
How do you use the yum module in an Ansible playbook to install a yum package?
Solution
Prerequisites
This assumes you have installed Ansible and configured a managed node to work with it. If you need assistance with this, see this posting.
Procedures
1.
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Continue reading “How Do You Write an Ansible Playbook to Install a Yum Package?”