Provide tooling for debugging images

[ryanemerson]

The image is based upon ubi-minimal in order to reduce it's footprint. Consequently, the image does not have many of the tools that developers are accustomed to when debugging issues. However, additional packages can be installed at image build time.

What packages do we require for the most common debugging tasks?

[rigazilla]

Not required but I would consider:
vi
more
tar (if I'm not wrong this is required to copy things to/from pod)
ps

[danberindei]

@rigazilla more, really? :))

[tristantarrant]

• Editor: I think nano would be the smallest thing we can package
• Pager: Not sure we need one (use the editor), but I'd go with less
• Sockets and files: lsof (it can list both sockets and file descriptors)
• Network configuration: ip which can list interface addresses and routes
• Process tool: ps (Although you can probably use lsof to get similar results)

I see the image already contains:

• grep for filtering
• coreutils contains a bunch of useful stuff like sort, uniq, tail, etc
• bsdtar is a tar replacement that has built-in support for gzip compression

Copying files from a container can be achieved using [docker|podman] cp ...

[ctron]

• find from findutils
• unzip (good for JAR files)

[tristantarrant]

We could also provide a little help page that is shown when logging into an interactive shell that tells users how to retrieve information (e.g. ip address show to list all network interfaces and addresses)

[ryanemerson]

Good idea! I think a help page will be very useful.

[tristantarrant]

Some recipes:
ps -fC java to get the PID of the java process
ss -t -a get all TCP sockets
ss -u -a get all UDP sockets
lsof |grep -v "IPv[46]" list all open files excluding network sockets

[belaban]

My wishlist:

• netstat
• nc (netcat)
• ping

[tristantarrant]

ss does what netstat does

[belaban]

Does it dump the routing table (netstat -nr), too? How about showing multicast groups (netstat -ng)?
If it does that, no problem, let's minimize what we're adding to an image.

[tristantarrant]

For that, we will use ip which can print interface, route and memberships

[rigazilla]

@rigazilla more, really? :))

more or less :)