Zombie killer for AE5 <= 5.4.1

This repository implements a hotfix that implements zombie process collection for AE5 sessions, jobs, and deployments. When successfully completed, the tini binary is inserted into PID 1, and all other processes become children of tini. This process ensures full signal propagation and zombie collection.

Installation should introduce minimal disruption to a running cluster, and can easily be reversed if needed:

1. Copy the contents of this repository to /opt/anaconda/tini on the master node.
2. Enter the Gravity environment and move to this directory.
3. Run download_tini.sh to download a tini binary. This scripts grabs a valid version of the binary and verifies its signature. If for any reason this fails—for instance, if your firewall blocks access—you can manually download the tini binary from this link: https://github.com/krallin/tini/releases/download/v0.19.0/tini
4. Run install_tini.sh. This will build new docker images for both sessions and deployments/jobs, push them to the internal registry, and modify the workspace and deploy deployments to use them. This will cause these deployments to restart, which will interrupt session and job/deployment operations for approximately 1 minute. However, existing sessions and deployments/jobs will not be disturbed.

If you wish to revert these changes, run remove_tini.sh. This will revert the changes to the workspace and deploy deployments to point to the stock images. As with step 4 above, this will interrupt operations on sessions, jobs, and deployments for approximately 1 minute.

Both install_tini.sh and remove_tini.sh can be run multiple times in succession without problems; the deployments will not be interrupted if no change is required.