[reconfigurator] ClickHouse XML generation types

[karencfv]

Overview

This commit adds a library to generate ClickHouse replica server and keeper configuration files. A lot of the code in the clickhouse-admin/types directory has been copied over from clickward, but there are several additions and modifications:

• New new() and default() methods that set default Oxide values.
• File generation is per node, as opposed to all files generated in a single directory like clickward.

Usage

To generate a replica server configuration file:

let keepers = vec![
    KeeperNodeConfig::new("ff::01".to_string()),
    KeeperNodeConfig::new("ff::02".to_string()),
    KeeperNodeConfig::new("ff::03".to_string()),
];

let servers = vec![
    ServerNodeConfig::new("ff::08".to_string()),
    ServerNodeConfig::new("ff::09".to_string()),
];

let config = ClickhouseServerConfig::new(
    Utf8PathBuf::from(config_dir.path()),
    ServerId(1),
    Utf8PathBuf::from_str("./").unwrap(),
    Ipv6Addr::from_str("ff::08").unwrap(),
    keepers,
    servers,
);

config.generate_xml_file().unwrap();

To generate a keeper configuration file:

let keepers = vec![
    RaftServerConfig::new(KeeperId(1), "ff::01".to_string()),
    RaftServerConfig::new(KeeperId(2), "ff::02".to_string()),
    RaftServerConfig::new(KeeperId(3), "ff::03".to_string()),
];

let config = ClickhouseKeeperConfig::new(
    Utf8PathBuf::from(config_dir.path()),
    KeeperId(1),
    keepers,
    Utf8PathBuf::from_str("./").unwrap(),
    Ipv6Addr::from_str("ff::08").unwrap(),
);

config.generate_xml_file().unwrap();

Purpose

As part of the work to roll out replicated ClickHouse, we'll need to dynamically generate the node configuration files via the clickhouse-admin service. This commit is part of the work necessary to do so.

Related: #5999 , #3824

[karencfv]

These ports are the default ClickHouse ports https://clickhouse.com/docs/en/guides/sre/network-ports

[karencfv]

The datastore_path and config_dir must be different directories. The clickhouse_{server|keeper} zones will have the clickhouse files like logs in the datastore directory, and the configuration files will need to live in in /opt/oxide/clickhouse_{server|keeper}/config.d/config_{server|keeper}.xml

[andrewjstone]

Makes sense. Thanks.

[andrewjstone]

Karen, this looks great! Just some minor comments.

[andrewjstone]

Makes sense. Thanks.

[karencfv]

Thanks for the review @andrewjstone! I'll update the PR with your comments