TLS is not working

[Damian Dąbrowski]

Seems like TLS in oslo.cache is not working(at least for some backends).

I created a simple script to test memcached connection: https://paste.openstack.org/show/bJPQRPsq953Hojl1cFMA/

Memcached instance is configured to serve TLS.

With dogpile.cache.memcached I see:

Apr 25 21:09:34 aio1-memcached-container-7f83bd44 systemd-memcached-wrapper[13218]: SSL connection failed with error code : 1 : Success
Apr 25 21:09:34 aio1-memcached-container-7f83bd44 systemd-memcached-wrapper[13218]: accept4(): Resource temporarily unavailable

On tcpdump I can see plain http traffic:

# tcpdump -i any 'host 172.29.238.233' -s 65535 -A -tttl | grep get
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on any, link-type LINUX_SLL (Linux cooked v1), capture size 65535 bytes
U[......get 274f7b9675887be609cf0d726a0395b3d1f7a815

With dogpile.cache.bmemcached it looks better: https://paste.openstack.org/show/bXW8pcHtigoIg5noXhoC/

Environment:
python 3.8.10
oslo.cache 3.3.1
memcached 1.5.22

[Takashi Kajinami (kajinamit)]

The dogpile.cache.memcached backend does not support tls connection. This is the limitation caused by underlying library.

We have introduced a validation to reject that wrong usage. See https://review.opendev.org/c/openstack/oslo.cache/+/907330 .

[Damian Dąbrowski (damiandabrowski)]

thanks!