add gcc to quickstart yum packages and getting started prerequisites

[ginglis13]

Signed-off-by: Gavin Inglis [email protected]

Issue #, if available:

n/a

Description of changes:

Noticed in going through the firecracker-containerd quickstart for Amazon Linux that by default, gcc is not installed. add that as a yum package to be installed. Just copy-pasting as is will run into an error of gcc not found.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[Kern--]

Can you update the getting started guide as well with an explanation of what requires gcc?

[austinvazquez]

Does this need to be included on RPM based instances as well?

[ginglis13]

Can you update the getting started guide as well with an explanation of what requires gcc?

Sure thing, added a line to the gettting started guide - building the in-VM agent depends on gcc: https://github.com/firecracker-microvm/firecracker-containerd/blob/279a03c70541cd355f4f4a8adda0480fbc6fb95d/agent/Makefile#L24-L29

Does this need to be included on RPM based instances as well?

This change does cover the RPM instance (AL2/yum). I tested on a fresh Debian instance, no issues there so no update required to the Debian scripts/instructions.

[kzys]

What was the error you got by not having gcc? I believe that firecracker-containerd doesn't have C dependencies.

[ginglis13]

What was the error you got by not having gcc? I believe that firecracker-containerd doesn't have C dependencies.

The error is gcc not in PATH in building the agent. I think there is a C dependency on using the Go linker. Here is a fresh AL2 ec2 instance where I've simply copy-pasted our quickstart guide up until sg docker -c 'make all image firecracker':

$ sg docker -c 'make all image firecracker'
make -C agent EXTRAGOARGS=
make[1]: Entering directory `/home/ec2-user/firecracker-containerd/agent'
go build  -ldflags "-X main.revision=279a03c70541cd355f4f4a8adda0480fbc6fb95d" -o agent
...
/home/ec2-user/.go/pkg/tool/linux_amd64/link: running gcc failed: exec: "gcc": executable file not found in $PATH

[kzys]

Can you force internal linking? Not really sure why it is doing external linking.

https://github.com/bazelbuild/rules_go/issues/2719#issuecomment-736871039

[ginglis13]

Can you force internal linking? Not really sure why it is doing external linking.

bazelbuild/rules_go#2719 (comment)

I can by passing -linkmode=internal to ldflags; I'm then seeing all other invocations of go build (e.g. for runtime, examples, volume, snapshotter, etc.) also attempt to use gcc as external linker, so would need to provide this linkmode flag to those rules as well...

Better option if we don't want to include gcc installation in quickstart/getting started is to change sg docker -c 'make all image firecracker' to CGO_ENABLED=0 sg docker -c 'make all image firecracker', since CGO_ENABLED=0 will use Go's internal linker, and this one env variable is a cleaner change than adding linkmode=internal to all of our Makefile rules

@kzys would you prefer that change to the quickstart over having users install gcc?

[kzys]

Sorry for the very late reply. This is good to go.