@krasavindy,

To install tools in a container, normally we have the two ways below:

1. Add the following commands (see Install the mssql-server-fts on Ubuntu) to the RUN instruction in the Dockerfile. When building the image, the mssql-server-fts will be installed.

   sudo apt-get update 
   sudo apt-get install -y mssql-server-fts
   

   In this way, you need to create a customized docker image based on the official sql server docker image, and add above commands in the Dockerfile of the customized image. Then you can use this customized image in your workflow.

2. If you do not want to create new image, after the container started, you can execute above commands in the container to install the mssql-server-fts.
   Unlike container job (jobs.<job_id>.container), the steps in the job will not run the service container. However, there is an option to set volumes for the service container to use (jobs.<job_id>.services.<service_id>.volumes).
   You can try to use above commands to install the mssql-server-fts on the runner machine, then set a volume to share the installation directory of mssql-server-fts between runner machine and service container.