Having trouble logging into an AWS instance using an SSH key? I was too and when I finally figured out what the issue was I was kicking myself. Recently I was called to assist figuring out information about a clients AWS deployment for a project where the original developers were no longer available or answering questions. Most of the instances that I initially worked on had no issues once I was able to obtain the correct SSH key pem file from Amazon. When the project was closing down I was asked to assist backing things up and it appeared the SSH key was failing for two of the instances which also happened to be the oldest two instances (2 years old). Below I describe the error I was seeing via SSH as well as the easy resolution to the problem.
When installing the acidbase package on Ubuntu Linux there are numerous popups that require answers. Some of those variables are covered in this article however there is one that when searching debconf selections for it isn’t listed with acidbase so it can be harder to locate. Below I display the popup in question and describe how to setup a debconf variable to get around it.
If you are putting together a script that uses wget to post data to various URL’s it is likely that you do not want wget to save the response back from the server in files. You can easily get around this by specifying the output file that wget save to with the -O switch. Below is an example of what would happen when the -O switch is not used followed by an example of using wget with the -O switch outputting the results to /dev/null.
It can be useful to know the debconf variables for an application you are going to install on Ubuntu Linux before installing the application. Below are the possible debconf variables to set for acidbase when installing on Ubuntu Linux 12.04 Precise Pangolin.
It can be useful to set temporary environment variables from the command line in Linux. Even more useful is the output of a long command being set to a single environment variable. Below I show an example of setting an environment variable followed by setting an environment variable to the output of a command or string of commands.