A compute's hostname and login go unquoted into the libvirt connection URI
(qemu+ssh://login@host/system, qemu+tcp://host/system, qemu+tls://...) and,
for an SSH compute, into the ssh command line of the DRBD status view. They
were barely validated: validate_hostname used re.match with a negated class,
so it caught only a leading special character, and login was never checked.
A hostname like "192.0.2.1/system?command=/path" injected a libvirt URI
parameter (verified: connecting ran the named command through the ssh
wrapper), and TLS/SSH parameters such as no_verify, pkipath, socket or
netcat could be added the same way; a login like "-oProxyCommand=..." became
an ssh option. The DRF ComputeSerializer applied neither check, and
validate_name tested a string literal instead of its argument, so it never
raised.
validate_hostname now accepts only an IPv4 address or a host name with
fullmatch (no scheme, port, path, query, whitespace or IPv6 literal; IPv6 is
left out until the URI building brackets it). validate_login accepts an empty
value (TCP falls back to the server's authentication, the socket transport
ignores the login) or a plain name with no leading "-". Both sit on the
Compute model fields, so the forms and the DRF serializer (which copies model
validators onto its fields) reject the values; a migration records the
metadata. validate_name checks its argument. drbd_status validates the login
and hostname before building login@host and ends ssh option parsing with
"--"; an existing or bypassed bad row is skipped rather than run.
Tests: hostname/login validators accept real values and reject URI and
option injection; the SSH form and the serializer (create, and an empty TCP
login) enforce them; drbd_status skips an injecting target. Checked the real
test computes still validate. The new tests fail on the previous code.
Migration is client-driven: libvirt sends the VM's memory to the
destination's own host name unless a migration URI is given, and the
app never gave one. Where the hosts cannot resolve each other's names
(or the names point at a management network) every migration failed
with "Unable to resolve address '<host name>' service '49152'".
A compute now has an optional migration address (an IP address or a
host name, no scheme or port), editable in the compute form and the
API. A VM migrating to that compute is sent to tcp://<address>
(bracketed for IPv6). Empty, the default for existing computes, keeps
the previous behavior. The compute's host name is not reused, because
for SSH computes it can be an ssh_config alias.
The migration log entry names the address when one is set.
libvirt has no timeout for opening a connection. Measured in the test
setup: an unreachable host blocked qemu+tcp for 135 s and qemu+ssh for
133 s; a daemon that accepts and never answers blocks forever. Gunicorn
runs sync workers and the instance list connects to every compute, so
one unreachable compute held a worker for minutes per page load.
- A connection is opened in a helper thread, at most one per
connection at a time. The request waits LIBVIRT_CONNECT_TIMEOUT
(default 5 s). An open nobody waits for any more keeps running; until
it ends, requests get its error at once, and if it succeeds later the
connection is used. A failed open is not repeated for
LIBVIRT_RETRY_AFTER (default 30 s). A stuck host holds one thread and
does not keep other hosts from connecting.
- qemu+ssh runs ssh through vrtManager/libvirt-ssh (the URI's command
parameter), which adds ConnectTimeout=10 and BatchMode=yes, so an
abandoned ssh process ends and no prompt can hang. The user's ssh
configuration (aliases, ProxyJump, keys) still applies.
- The close callback acts only for the connection it was registered
for: a late callback of a replaced connection dropped its successor.
The reason is reported as text. A connection that closed before it
was published is an error.
- Compute.status is a bool (it returned the exception object, so the
"host is down" check in refresh_instance_database never fired); the
message is Compute.connection_error.
Unit tests cover the timeout, retry delay, late success, single open,
a stuck host next to a healthy one and the close callback. Live tests
(vrtManager/test_live_connection.py), for TCP and SSH computes of the
test setup: an unreachable address (no ssh left after 10 s), an endpoint
that never answers, a slow open completing later, a host that goes
silent on an established connection (keepalive ends calls within 45 s,
the next request reconnects), an ssh_config alias and a ProxyJump host.
