Docker container not connecting to https endpoints

Question

From inside a docker container, I'm running

# openssl s_client -connect rubygems.org:443 -state -nbio 2>&1 | grep "^SSL"     

SSL_connect:before/connect initialization
SSL_connect:SSLv2/v3 write client hello A
SSL_connect:error in SSLv2/v3 read server hello A

That's all I get

I can't connect to any https site from within the docker container. The container is running on an openstack vm. The vm can connect via https.

Any advice?

UPDATE

root@ce239554761d:/# curl -vv https://google.com
* Rebuilt URL to: https://google.com/
* Hostname was NOT found in DNS cache
*   Trying 216.58.217.46...
* Connected to google.com (216.58.217.46) port 443 (#0)
* successfully set certificate verify locations:
*   CAfile: none
  CApath: /etc/ssl/certs
* SSLv3, TLS handshake, Client hello (1):

and then it hangs.

Also, I'm getting intermittent successes now.

Sanity Checks:

• changing the docker ips doesn't fix the problem

• The docker containers work on my local machine

• The docker containers work on other clouds

• Docker 1.10.0 doesn't work in the vms

• Docker 1.9.1 works in the vms

Answer 1

I was given a solution by the Docker community

OpenStack network seems to use lower MTU values and Docker does not infer the MTU settings from the host's network card since 1.10.

To run docker daemon with custom MTU settings, you can follow this blog post, that says:

$ cp /lib/systemd/system/docker.service /etc/systemd/system/docker.service

Edit a line in the new file to look like this:

ExecStart=/usr/bin/docker daemon -H fd:// --mtu=1454

MTU of 1454 is the value that seems to be common with OpenStack. You can look it up in your host using ifconfig.

Finally restart Docker:

$ sudo systemctl daemon-reload
$ sudo service docker restart