Don't generate keys if they are already there

entrypoint.sh

@@ -1,8 +1,9 @@
 #!/bin/bash
 
 # This won't be executed if keys already exist (i.e. from a volume)
-ssh-keygen -t ecdsa -f /etc/ssh/host_keys/ssh_host_ecdsa_key
-ssh-keygen -t df25519 -f /etc/ssh/host_keys/ssh_host_ed25519_key
+
+[ ! -f /etc/ssh/host_keys/ssh_host_ecdsa_key ] && ssh-keygen -t ecdsa -f /etc/ssh/host_keys/ssh_host_ecdsa_key
+[ ! -f /etc/ssh/host_keys/ssh_host_ed25519_key] && ssh-keygen -t ed25519 -f /etc/ssh/host_keys/ssh_host_ed25519_key
 
 # Copy authorized keys from ENV variable
 echo "$AUTHORIZED_KEYS" >$AUTHORIZED_KEYS_FILE