Skip to main content
Version: v25.1.1

Hedgehog switch credentials update

Updating switch user credentials in the Hedgehog fabricator spec

Purpose​

After the Hedgehog fabric is provisioned, the fabricator CRD still holds the default switch user credentials from the installer ISO. Patching the spec before switch installation ensures switches receive operator-defined credentials during SONiC provisioning.

Two sets of credentials are configured:

  • admin (role: admin) and op (role: operator) — users on each managed switch
  • control node user — the fabricator's record of the Hedgehog VM core user; updating this does not affect OS-level credentials but keeps the spec consistent with the manual changes made via update-ssh-keys during bootstrap

The fabricator reconciler propagates changes automatically; no additional trigger is needed.

When to run​

After Phase 3 of bootstrap (--bootstrap --tags hedgehog-fabric) completes and before booting any switch into ONIE for SONiC installation. Updating after switch installation is also possible, but requires re-provisioning the affected switches to apply the new credentials.

Prerequisites​

  • SSH access to the Hedgehog control node VM as core
  • New passwords chosen for the admin and op switch users
  • SSH public keys to authorise on switches (collected in Step 2)

Step 1: SSH to the Hedgehog control node​

From the bastion node:

ssh core@<hedgehog-control-ip>

Steps 2–5 run inside this SSH session.

Step 2: Collect the current authorized keys​

The same keys registered on the Hedgehog VM should be authorized on the switches. List them, excluding comment lines:

cat /home/core/.ssh/authorized_keys | grep -v '#'

Copy the output — these are the values for the authorizedKeys arrays in Steps 4 and 5.

Step 3: Generate password hashes​

openssl passwd -5 produces a SHA-512 crypt hash (the $5$… format used in /etc/shadow). Generate one hash per switch user:

openssl passwd -5 <new-admin-password>
openssl passwd -5 <new-op-password>

Note each hash; the full $5$… string is used verbatim in the patch commands.

For Step 5 (control node consistency patch), use the hash of the password already set on the core user during the VM credential bootstrap — not a new password. Generate it now if it was not noted at that time:

openssl passwd -5 <core-user-password-from-bootstrap>

Step 4: Update switch user credentials​

Patch both switch users in a single call. Use a heredoc to avoid shell expansion of the $ characters in the password hashes:

kubectl patch fabricators.fabricator.githedgehog.com default -n fab --type=merge \
  -p "$(cat <<'EOF'
{
  "spec": {
    "config": {
      "fabric": {
        "defaultSwitchUsers": {
          "admin": {
            "role": "admin",
            "password": "$5$<admin-hash>",
            "authorizedKeys": ["ssh-ed25519 AAAA...", "ssh-ed25519 AAAA..."]
          },
          "op": {
            "role": "operator",
            "password": "$5$<op-hash>",
            "authorizedKeys": ["ssh-ed25519 AAAA...", "ssh-ed25519 AAAA..."]
          }
        }
      }
    }
  }
}
EOF
)"

Step 5: Update the control node user in the fabricator spec​

This keeps the fabricator's record consistent with the credentials set on the VM during bootstrap. It does not modify the OS-level core user account.

kubectl patch fabricators.fabricator.githedgehog.com default -n fab --type=merge \
  -p "$(cat <<'EOF'
{
  "spec": {
    "config": {
      "control": {
        "defaultUser": {
          "password": "$5$<control-hash>",
          "authorizedKeys": ["ssh-ed25519 AAAA...", "ssh-ed25519 AAAA..."]
        }
      }
    }
  }
}
EOF
)"

Step 6: Verify the patch was applied​

kubectl describe fabricators default -n fab

In the output, locate the spec.config.fabric.defaultSwitchUsers and spec.config.control.defaultUser sections. Confirm that the password fields show the new hashes (not the ISO defaults) and that authorizedKeys lists all expected public keys.

Verify​

  • kubectl describe fabricators default -n fab output shows updated password hashes for admin and op
  • kubectl describe fabricators default -n fab output shows updated authorizedKeys for admin and op
  • Fabricator control.defaultUser reflects the keys set on the VM during bootstrap
  • Switches installed after this step accept SSH login with the authorised keys