feat: add support config allow_connection and some things about read only routing

[zhuatuzilo]

Feature: add two variable in inventory:

mssql_ha_secondary_role_allow_connections - READ_ONLY or ALL or NO - default ALL

mssql_ha_read_only_routing_list - e.g. ('node-4','node-6') - if undefined or empty value , will not set read only routing list - default is undefined

See this for possible values and more info - https://learn.microsoft.com/en-us/sql/database-engine/availability-groups/windows/configure-read-only-routing-for-an-availability-group-sql-server?view=sql-server-ver16

add auto set read only routing url like 'tcp://node-4:1433', '1433' from var: mssql_tcp_port

it's work in my local, I test two example
1、the variable is defined as
mssql_ha_secondary_role_allow_connections: READ_ONLY
mssql_ha_read_only_routing_list: ('node-5','node-6')
result: as expected

2、the variable is undefined
result: allow connections be 'ALL', read only routing list be NULL, as expected

Reason: we need READ ONLY ROUTING LIST used to provide read write separation and load balance for read only (or priority of human control for read only), if need READ ONLY ROUTING LIST then must defined READ ONLY ROUTING URL at first.

SECONDARY_ROLE ( ALLOW_CONNECTION='READ_ONLY') used to verify attribute defined in the connection string on replica which is secondary role, like ApplicationIntent=ReadOnly.

Result: Users can configure an Always On availability group to support read-only routing

[spetrosi]

@zhuatuzilo that's a huge improvement, many thanks for your contributions.

I need to cover these new variables with tests. What would be the verification steps to test that this setup works?
In our CI we can run multihost tests - i.e. provision 1 control node and 3 managed nodes, and then build an inventory, and playbook, and run it.
We do this e.g. in https://github.com/linux-system-roles/mssql/blob/main/tests/tests_configure_ha_cluster_external.yml#L182-L263

Would you be able to come up with similar verification tasks?

[richm]

Suggested change

	promotable: yes
	promotable: true

[richm]

I know the README example uses yes - but this fails ansible-lint - Ansible strongly prefers the use of true/false

[richm]

@zhuatuzilo thank you for the submission. Can you please explain a bit more about why a user would need to use this new feature?

[zhuatuzilo]

@zhuatuzilo thank you for the submission. Can you please explain a bit more about why a user would need to use this new feature?

we need READ ONLY ROUTING LIST used to read write separation and load balance for read only (or priority of human contrl for read only), if need READ ONLY ROUTING LIST is work must defined READ ONLY ROUTING URL at first.

SECONDARY_ROLE ( ALLOW_CONNECTION='READ_ONLY') used to veify attribute defined in the connection string on replica which is secondary role,
like ApplicationIntent=ReadOnly.
see the doc from microsoft: https://learn.microsoft.com/zh-cn/sql/database-engine/availability-groups/windows/configure-read-only-routing-for-an-availability-group-sql-server?view=sql-server-ver16

[zhuatuzilo]

@zhuatuzilo that's a huge improvement, many thanks for your contributions.

I need to cover these new variables with tests. What would be the verification steps to test that this setup works? In our CI we can run multihost tests - i.e. provision 1 control node and 3 managed nodes, and then build an inventory, and playbook, and run it. We do this e.g. in https://github.com/linux-system-roles/mssql/blob/main/tests/tests_configure_ha_cluster_external.yml#L182-L263

Would you be able to come up with similar verification tasks?

sorry
this is a bit difficult for me