mgr/cephadm: re-use old ip when re-adding hosts if necessary

When a host is re-added without an explicit ip we can default to the old
ip we had stored for the host rather than either keeping the loopback
address or throwing an exception. We only want to actually error when
the only options left are error or use a resolved loopback address

Fixes: https://tracker.ceph.com/issues/53438
Signed-off-by: Adam King <adking@redhat.com>

diff --git a/src/pybind/mgr/cephadm/module.py b/src/pybind/mgr/cephadm/module.py
index 0a3a222e280734333eea4be8a801e84aac1cbe9e..fdb6ca616c882b1da11f1b361305db2ebb0a5563 100644 (file)
--- a/src/pybind/mgr/cephadm/module.py
+++ b/src/pybind/mgr/cephadm/module.py
@@ -1,5 +1,6 @@
 import json
 import errno
+import ipaddress
 import logging
 import re
 import shlex
@@ -1346,11 +1347,6 @@ class CephadmOrchestrator(orchestrator.Orchestrator, MgrModule,
         return image
 
     def _check_valid_addr(self, host: str, addr: str) -> str:
-        # make sure mgr is not resolving own ip
-        if addr in self.get_mgr_id():
-            raise OrchestratorError(
-                "Can not automatically resolve ip address of host where active mgr is running. Please explicitly provide the address.")
-
         # make sure hostname is resolvable before trying to make a connection
         try:
             ip_addr = utils.resolve_ip(addr)
@@ -1373,6 +1369,15 @@ Then run the following:
 > ssh -F ssh_config -i ~/cephadm_private_key {self.ssh_user}@{addr}'''
             raise OrchestratorError(msg)
 
+        if ipaddress.ip_address(ip_addr).is_loopback and host == addr:
+            # if this is a re-add, use old address. otherwise error
+            if host not in self.inventory or self.inventory.get_addr(host) == host:
+                raise OrchestratorError(
+                    (f'Cannot automatically resolve ip address of host {host}. Ip resolved to loopback address: {ip_addr}\n'
+                     + f'Please explicitly provide the address (ceph orch host add {host} --addr <ip-addr>)'))
+            self.log.debug(
+                f'Received loopback address resolving ip for {host}: {ip_addr}. Falling back to previous address.')
+            ip_addr = self.inventory.get_addr(host)
         out, err, code = self.wait_async(CephadmServe(self)._run_cephadm(
             host, cephadmNoImage, 'check-host',
             ['--expect-hostname', host],