"fleet apply --output" fails on empty kubeconfig

[mearsten]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

Take an valid empty kubeconfig, then try to render a bundle locally. Fleet CLI is supposed to work with no k8s cluster accessible:

% cat kubeconfig-empty.yaml
apiVersion: v1
kind: Config
preferences: {}
clusters: []
users: []
contexts: []

% env KUBECONFIG=kubeconfig-empty.yaml ./fleet-linux-amd64-0.15.4 apply -o bundle.yaml some ./some || echo "rc=$?"
rc=1

% env KUBECONFIG=kubeconfig-empty.yaml ./fleet-linux-amd64-0.16.0-rc.4 apply -o bundle.yaml some ./some || echo "rc=$?"
rc=1

% ls -l bundle.yaml
"bundle.yaml": No such file or directory (os error 2)

% ./fleet-linux-amd64-0.15.4 --version; ./fleet-linux-amd64-0.16.0-rc.4 --version
fleet version v0.15.4 (7b97db764df7de385e0572eab6da959e0bd22569)
fleet version v0.16.0-rc.4 (4b6976899c8cfc16317e7e5d610c74caa56ddd34)

It is working fine with a dummy cluster added:

% cat kubeconfig-dummy.yaml
apiVersion: v1
kind: Config
preferences: {}
clusters:
  - {name: dummy, cluster: {server: whatever}}
contexts:
  - {name: dummy, context: {cluster: dummy}}
current-context: dummy

% env KUBECONFIG=kubeconfig-dummy.yaml ./fleet-linux-amd64-0.15.4 apply -o bundle.yaml some ./some || echo "rc=$?"

% ls -l bundle.yaml
.rw------- 86k user 10 Jul 13:30 bundle.yaml

Expected Behavior

fleet apply -o bundle.yaml … should produce output with valid empty kubeconfig.

Steps To Reproduce

All info is in the "Current behaviour" section.

Environment

- Architecture: amd64
- Fleet Version: 0.15.4, 0.16.0-rc.4
- Cluster: N/A

Logs

Anything else?

It seems the CLI tries to detect whether it is run locally or in a pod and fails:

% env KUBECONFIG=kubeconfig-empty.yaml strace -et=%file -es=none -eq=all -s99999 -f ./fleet-linux-amd64-0.15.4 apply -o bundle.yaml some ./some
…
[pid 1617654] openat(AT_FDCWD, "kubeconfig-empty.yaml", O_RDONLY|O_CLOEXEC) = 3
[pid 1617654] newfstatat(AT_FDCWD, "/var/run/secrets/kubernetes.io/serviceaccount/token", 0xc0007cd628, 0) = -1 ENOENT (No such file or directory)

It shouldn't do that check if run with -o / --output option.