How to reset the initialing passwords of DevOps tools (Jenkins, Rancher, Nexus, etc.) or get the bootstrap password manually?

The admin password of our DevOps tools (for example Jenkins, Rancher, etc.) was unlocked or we forgot its admin password. How to set or retrieve the admin password? How to reset it? When we install DevOps tools with Terraform, we got a “local-exec” provisioner error and it didn’t give us the bootstrap password in the output, or the bootstrap pod is not initialized and we don’t get the bootstrap password. How to get the bootstrap password of our DevOps tools (for example Rancher, Nexus repository, etc.)?
In this article, I tried to collect the commands that we will use to reset the login passwords for DevOps programs when we cannot remember. Also, I tried to collect the commands that we will get the bootstrap password manually. I tried them working, I documented it for you.
Now, we will do them step by step again.

Important Note: If you have similar solutions for different DevOps tools, write them in the comments section. So, you can contribute to the creation of a good source document on this subject. I will also include them in the article with your name or by referring to the link you provided. Happy Clouding…

Topics we will cover:

1. How to reset Jenkins admin password?

2. How to reset or get the Rancher bootstrap password?

3. How to get the Nexus repository bootstrap password?

4. How to Reset your Azure DevOps repository password?

5. How to reset the Gitlab admin password using Rake Task on Ubuntu 21.04?

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