standardizing IPv4 networking in SCS

[cah-patrickthiem]

This is the initial draft document to standardize IPv4 networking in the context of SCS.

[markus-hentsch]

(EDIT: comment moved here: https://github.com/SovereignCloudStack/issues/issues/167#issuecomment-2044933327)

[cah-patrickthiem]

Current status of this topic & some open questions:

• this standard will be a rather more general standard, with important topics directly associated with IPv4 handling and linking to other standards for more in depth explanations (e.g. Security Group standard)

Key suggestions:

• IPv6 MUST be available
• IPv4 SHOULD be available
• subnet pools SHOULD be used for IPv6
• Border Gateway Protocol (BGP): IPv6 MUST - IPv4 MAY - SHOULD
• Neutron Routers MUST be used
• OVN or L3agent SHOULD be used as high availability service deployments
• Standard external networks MUST NOT be made accessible as shared networks
  • needs further investigation regarding "port security"
• External networks and subnets MUST be configured with --no-dhcp
• SCS conform CSPs MAY use RBAC and VPNaaS Neutron plugins
  • need to investigate further on what plugins & extensions are really available and up to date
  • RBAC MUST set to admin only mode
• security Groups SHOULD be enabled by default
• standard quota of floating IPs and routers MAY be rather small
  • min quota SHOULD be > 1 floating IP
  • same for router usage
• SCS CSPs SHOULD implement monitoring solutions to track the utilization of IPv4 floating IPs
  • probably makes more sense to specify the tool from the SCS side which should be used
    • we would need to build it ourselves probably
• SCS clouds SHOULD adopt the naming convention scs-external-net for external
  • we decided to drop that entirely
• Floating IPs MUST be enabled
• multiple subnets MAY be used in the standard external network

Open Questions:

• Should IPv4 and IPv6 networks be standardized in one document?

Todos:

• check port security
• investigate on Neutron router plugins and extensions
• create architectural overview regarding IPv4 networking in SCS

[kgube]

I'm trying to restructure the standard a bit and add some background and justification to the proposals. It's not yet at a point where want to make a PR but I'm keeping the draft in a hedgedoc: https://input.scs.community/rRwNRXloTXu6cmG_19cr_g

EDIT: I moved the draft to its own PR: https://github.com/SovereignCloudStack/standards/pull/572

[cah-patrickthiem]

For the record, that topic was discussed recently in a SCS IaaS meeting, initiated by kgube. One of the questions was, if we want to define all network topics in one single network standard and the answer was clearly a no. Next we will figure out what network aspect will get its own standard document and what aspect might still be missing.