dhcp: T3316: Migrate dhcp/dhcpv6 server to Kea

[sarthurdev]

Change Summary

This PR refactors the DHCP and DHCPv6 servers and migrates to use the newly available ISC Kea replacing EOL ISC DHCP Server.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T3316

Related PRs:

• dhcp: T3316: Disable Kea services vyos-build#336

Component(s) name

dhcp-server, dhcpv6-server

Proposed changes

DHCPv4:

• All section parameters (global-parameters, subnet-parameters, ...) are now invalid and removed on migration.
• host-decl-name node removed, always enabled in Kea.
• ping-check is no longer available (https://kb.isc.org/docs/why-doesnt-kea-support-ping-check).
• per-subnet failover with enable-failover is not supported, New high availability supports all subnets defined on all peers.
• Added CA/certificate nodes to failover to support Kea TLS secured failover (untested)

DHCPv6:

• Subnet PD node changed to use defined prefix-length and delegated-length, range not supported in Kea. Migration script tries to convert existing ranges to a prefix length, where possible.
• Temporary addresses are removed as no longer supported in Kea (https://kea.readthedocs.io/en/kea-2.2.0/arm/dhcp6-srv.html#dhcpv6-server-limitations)
• Add shared-network-name <name> interface <ifname> to bind the shared network and subnets to a specific interface

How to test

DEBUG - Running Testcase: /usr/libexec/vyos/tests/smoke/cli/test_service_dhcp-server.py
DEBUG - test_dhcp_exclude_in_range (__main__.TestServiceDHCPServer.test_dhcp_exclude_in_range) ... ok
DEBUG - test_dhcp_exclude_not_in_range (__main__.TestServiceDHCPServer.test_dhcp_exclude_not_in_range) ... ok
DEBUG - test_dhcp_failover (__main__.TestServiceDHCPServer.test_dhcp_failover) ... ok
DEBUG - test_dhcp_multiple_pools (__main__.TestServiceDHCPServer.test_dhcp_multiple_pools) ... ok
DEBUG - test_dhcp_relay_server (__main__.TestServiceDHCPServer.test_dhcp_relay_server) ... ok
DEBUG - test_dhcp_single_pool_options (__main__.TestServiceDHCPServer.test_dhcp_single_pool_options) ... ok
DEBUG - test_dhcp_single_pool_range (__main__.TestServiceDHCPServer.test_dhcp_single_pool_range) ... ok
DEBUG - test_dhcp_single_pool_static_mapping (__main__.TestServiceDHCPServer.test_dhcp_single_pool_static_mapping) ... ok
DEBUG -
DEBUG - ----------------------------------------------------------------------
DEBUG - Ran 8 tests in 46.197s
DEBUG -
DEBUG - OK

...

DEBUG - Running Testcase: /usr/libexec/vyos/tests/smoke/cli/test_service_dhcpv6-server.py
DEBUG - test_global_nameserver (__main__.TestServiceDHCPv6Server.test_global_nameserver) ... ok
DEBUG - test_prefix_delegation (__main__.TestServiceDHCPv6Server.test_prefix_delegation) ... ok
DEBUG - test_single_pool (__main__.TestServiceDHCPv6Server.test_single_pool) ... ok
DEBUG -
DEBUG - ----------------------------------------------------------------------
DEBUG - Ran 3 tests in 15.921s
DEBUG -
DEBUG - OK

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[sarthurdev]

Drafted to fix op mode

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[c-po]

@sarthurdev can you fix the conflicts please?

[github-actions]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[c-po]

I think this is a good development candidate for VyOS 1.5

[sever-sever]

I think this is a good development candidate for VyOS 1.5

@c-po I agree! If it doesn't suit us, we will know about it.