Dwellers

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Dwellers is an VMWare EXSi instance installed on Dreadnought.

The goal of this server is to provide a Docker / OpenShift / Geard CentOS PaaS service.

Basic information

  • IPs:
    • 51.255.124.11
    • 2001:470:1f13:ce7:ca5:cade:fab:1e
  • Hostname: dwellers.nasqueron.org
  • Homepage: https://dwellers.nasqueron.org/
  • Configuration: 10 GB RAM and 4 core, burstable on request to 6 cores
  • OS: CentOS 8
  • ISP: SoYouStart (FR)
  • Network: OVH (FR)
  • Status: Used for Docker development and testing
  • Policy: Access for any Nasqueron or Wolfplex project
  • Started: 2014-07-13

Services

Containers

Ports table

The ports table is composed of the reserved-for-legacy-docker-migration- entries in rOPS: PORTS.

forum.nasqueron.org

Port prefix: 32

Provides a Discourse instance, to be used as a forum at http://forum.nasqueron.org/

First, update the configuration:

    cd /data/discourse/app/
    #ensure you have id_zr in the SSH agent with ssh-add -l
    #if not, and if you have trouble with an agent, alias ssh "ssh -i /root/.ssh/id_zr" should work
    make update

Then, launch db and cache containers:

    docker run -d -v /data/discourse/postgres:/var/lib/postgresql -e LC_ALL=C.UTF-8 --name=discourse-postgres postgres
    docker run -d --name discourse-redis redis

Finally, launch web container:

    docker run -d -v /data/discourse/app:/data/config -p 32000:3000 -p 32080:80 --link discourse-postgres:db --link discourse-redis:cache --name discourse-web nasqueron/discourse

At launch time, the web container can perform some tasks. Erase the dotfiles in /data/discourse/app/ to force them:

  • rake db:migrate if .database-initialized is not found
  • rake assets:precompile if .database-initialized is not found
  • regenerate language configuration and files if .language-set not found and a language file contains a language string

So to switch from English to French for example:

    echo fr > language
    rm .language-set

Also at launch time, the web container will populate config directory with missing config files before to create symlinks of these files to the Discourse web config folder. So, if you found a Discourse instance trying to find a database at localhost, don't forget to generate from discourse.conf.tmpl a discourse.conf file following instructions given above in update the configuration step.

Troubleshoot

How to point a domain here?

For your domains:

  • subdomain.domain.tld A 51.255.124.11
  • subdomain.domain.tld AAAA 2001:470:1f13:ce7:ca5:cade:fab:1e

To request a DNS update for domains using extensively the Nasqueron servers infrastructure:

  • subdomain.nasqueron.org CNAME www3.nasqueron.org
  • subdomain.espace-win.org CNAME www2.espace-win.org

How to access by SSH to an instance?

See the ports table to check if a port is assigned. We don't assign port if there is no reason general public got access to the VM by SSH. We assign port each time a stable address is needed (for example to talk with a Git server)

If the port is mapped:

   ssh -p <port> username@dwellers.nasqueron.org

If the port is unmapped, you can from Dwellers:

   docker ps
   docker inspect <instance id> #gets the local IP
   ssh <IP 172.*>

If you don't see the IP with docker inspect, check you use the instance id, not the image name.

Note: with recent Docker versions, you don't need to SSH anymore: you can use docker exec -it <container name> <your favorite shell> instead.

No network at boot time

Access the machine on the hypervisor, then:

Check the interface is up
   ip addr
   ifup ens192 # to bring it up
If you've reset the configuration and need to add again the IP
   ip addr add 51.255.124.11/32 dev ens192
Routing is probably the issue
   ip route add 91.121.86.254 dev ens192
   ip route add default via 91.121.86.254
Same for the case we can ping/ssh (slowly) from Ysul but not from the world
   ip route change 91.121.86.254 dev ens192
   ip route change default via 91.121.86.254
Reconfigure the IPv6 tunnel

At some point, the Linux route2 method stopped to work, but the Linux net-tools method still work.

   ip tunnel del he-ipv6
   ifconfig sit0 up
   ifconfig sit0 inet6 tunnel ::216.66.84.42
   ifconfig sit1 up
   ifconfig sit1 inet6 add 2001:470:1f12:ce7::2/64
   ifconfig sit1 inet6 add 2001:470:1f13:ce7:ca5:cade:fab:1e/64
   route -A inet6 add ::/0 dev sit1

Issue reproducible on a fresh CentOS 8.1 installation.

A port on the host doesn't reply (but does in Docker)

You can reset the iptables configuration. A script has been provided for that.

   $ systemctl stop docker
   $ /usr/sbin/reset-iptables
   $ systemctl start docker

If you're willing to restrict ports, you can use instead /root/reset-iptables-dwellers

You then need to reapply the mailserver network iptables rules.

From Docker and LXC, it's not possible to connect outside

It could be the net.ipv4.ip_forward switched from 1 to 0:

   sysctl net.ipv4.ip_forward=1

Or it could be an issue with iptables:

   systemctl stop docker
   iptables -t nat -F POSTROUTING
   iptables -t nat -A POSTROUTING -o ens192 -j MASQUERADE
   systemctl start docker

If you need to recreate the forwarding map (P91):

   iptables -t nat -I PREROUTING -i ens192 -p TCP -d 51.255.124.11/32 --dport 25 -j DNAT --to-destination 10.0.3.8:25
   iptables -t nat -I PREROUTING -i ens192 -p TCP -d 51.255.124.11/32 --dport 21080 -j DNAT --to-destination 10.0.3.8:80
   iptables -t nat -I PREROUTING -i ens192 -p TCP -d 51.255.124.11/32 --dport 110 -j DNAT --to-destination 10.0.3.8:110
   iptables -t nat -I PREROUTING -i ens192 -p TCP -d 51.255.124.11/32 --dport 143 -j DNAT --to-destination 10.0.3.8:143
   iptables -t nat -I PREROUTING -i ens192 -p TCP -d 51.255.124.11/32 --dport 465 -j DNAT --to-destination 10.0.3.8:465
   iptables -t nat -I PREROUTING -i ens192 -p TCP -d 51.255.124.11/32 --dport 587 -j DNAT --to-destination 10.0.3.8:587
   iptables -t nat -I PREROUTING -i ens192 -p TCP -d 51.255.124.11/32 --dport 993 -j DNAT --to-destination 10.0.3.8:993
   iptables -t nat -I PREROUTING -i ens192 -p TCP -d 51.255.124.11/32 --dport 995 -j DNAT --to-destination 10.0.3.8:995