Happy Friday all. I was hoping someone could point me in the right direction or clarify any limitations that could be impacting an issue I am having. I'm struggling to add a new set of hosts to my ceph cluster using cephadm and orchestration. When trying to add a host: "ceph orch host add <hostname> 172.31.102.41 --labels _admin" returns: "Error EINVAL: Can't communicate with remote host `172.31.102.41`, possibly because python3 is not installed there: [Errno 12] Cannot allocate memory" I've verified that the ceph ssh key works to the remote host, host's name matches that returned from `hostname`, python3 is installed, and "/usr/sbin/cephadm prepare-host" on the new hosts returns "host is ok". In addition, the cluster ssh key works between hosts and the existing hosts are able to ssh in using the ceph key. The existing ceph cluster is Pacific release using docker based containerization on RockyLinux8 base OS. The new hosts are RockyLinux9 based, with the cephadm being installed from Quincy release: ./cephadm add-repo --release quincy ./cephadm install I did try installing cephadm from the Pacific release by changing the repo to el8, but that did not work either. Is there a limitation is mixing RL8 and RL9 container hosts under Pacific? Does this same limitation exist under Quincy? Is there a python version dependency? The reason for RL9 on the new hosts is to stage upgrading the OS's for the cluster. I did this under Octopus for moving from Centos7 to RL8. Thanks and I appreciate any feedback/pointers. Gary I've added the log trace here in case that helps (from `ceph log last cephadm`) 2024-02-02T14:22:32.610048+0000 mgr.storage01.oonvfl (mgr.441023307) 4957871 : cephadm [ERR] Can't communicate with remote host `172.31.102.41`, possibly because python3 is not installed there: [Errno 12] Cannot allocate memory Traceback (most recent call last): File "/usr/share/ceph/mgr/cephadm/serve.py", line 1524, in _remote_connection conn, connr = self.mgr._get_connection(addr) File "/usr/share/ceph/mgr/cephadm/module.py", line 1370, in _get_connection sudo=True if self.ssh_user != 'root' else False) File "/lib/python3.6/site-packages/remoto/backends/__init__.py", line 35, in __init__ self.gateway = self._make_gateway(hostname) File "/lib/python3.6/site-packages/remoto/backends/__init__.py", line 46, in _make_gateway self._make_connection_string(hostname) File "/lib/python3.6/site-packages/execnet/multi.py", line 133, in makegateway io = gateway_io.create_io(spec, execmodel=self.execmodel) File "/lib/python3.6/site-packages/execnet/gateway_io.py", line 121, in create_io io = Popen2IOMaster(args, execmodel) File "/lib/python3.6/site-packages/execnet/gateway_io.py", line 21, in __init__ self.popen = p = execmodel.PopenPiped(args) File "/lib/python3.6/site-packages/execnet/gateway_base.py", line 184, in PopenPiped return self.subprocess.Popen(args, stdout=PIPE, stdin=PIPE) File "/lib64/python3.6/subprocess.py", line 729, in __init__ restore_signals, start_new_session) File "/lib64/python3.6/subprocess.py", line 1295, in _execute_child restore_signals, start_new_session, preexec_fn) OSError: [Errno 12] Cannot allocate memory During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/usr/share/ceph/mgr/cephadm/serve.py", line 1528, in _remote_connection raise execnet.gateway_bootstrap.HostNotFound(msg) execnet.gateway_bootstrap.HostNotFound: Can't communicate with remote host `172.31.102.41`, possibly because python3 is not installed there: [Errno 12] Cannot allocate memory The above exception was the direct cause of the following exception: Traceback (most recent call last): File "/usr/share/ceph/mgr/orchestrator/_interface.py", line 125, in wrapper return OrchResult(f(*args, **kwargs)) File "/usr/share/ceph/mgr/cephadm/module.py", line 2709, in apply results.append(self._apply(spec)) File "/usr/share/ceph/mgr/cephadm/module.py", line 2574, in _apply return self._add_host(cast(HostSpec, spec)) File "/usr/share/ceph/mgr/cephadm/module.py", line 1517, in _add_host ip_addr = self._check_valid_addr(spec.hostname, spec.addr) File "/usr/share/ceph/mgr/cephadm/module.py", line 1498, in _check_valid_addr error_ok=True, no_fsid=True) File "/usr/share/ceph/mgr/cephadm/serve.py", line 1326, in _run_cephadm with self._remote_connection(host, addr) as tpl: File "/lib64/python3.6/contextlib.py", line 81, in __enter__ return next(self.gen) File "/usr/share/ceph/mgr/cephadm/serve.py", line 1558, in _remote_connection raise OrchestratorError(msg) from e orchestrator._interface.OrchestratorError: Can't communicate with remote host `172.31.102.41`, possibly because python3 is not installed there: [Errno 12] Cannot allocate memory -- Gary Molenkamp Science Technology Services Systems Engineer University of Western Ontario molenkam@uwo.ca http://sts.sci.uwo.ca (519) 661-2111 x86882 (519) 661-3566