某天，由于Linux伺服器預設沒有DNS緩存功能，每次伺服器每通路一個http域名連結時，都會觸發一次DNS域名解析查詢，降低了調用API接口的時延，是以我司後續啟用的内網的dnsmasq DNS服務功能，需要将執行個體的DNS IP進行修改 登入一台controller source admin-openrc.sh neutron subnet-list +--------------------------------------+---------------------------------------------------+------------------+------------------------------------------------------+ | id | name | cidr | allocation_pools | +--------------------------------------+---------------------------------------------------+------------------+------------------------------------------------------+ | 333b430f-bffe-47ed-9c1c-14a33618f569 | HA subnet tenant 18649c1da2594d31988fd26baf15252b | 169.254.192.0/18 | {"start": "169.254.192.1", "end": "169.254.255.254"} | | 358321c0-6cbc-4ed7-a9e3-d8e7c3a6cf3a | 17216150 | 172.16.150.0/24 | {"start": "172.16.150.11", "end": "172.16.150.253"} | | 291efb02-af77-429f-bc9e-95b714a804da | 1040100 | 10.40.100.0/24 | {"start": "10.40.100.10", "end": "10.40.100.253"} | | ed517a74-736c-431d-8dd9-2b632395e6bb | 1040200 | 10.40.200.0/24 | {"start": "10.40.200.10", "end": "10.40.200.253"} | | 419229d1-45d9-4aec-9fdf-e9fde3d58757 | 17216100 | 172.16.100.0/24 | {"start": "172.16.100.11", "end": "172.16.100.253"} | | f7a13116-d091-4ad5-94fd-77a3c3f01ab5 | 1040150 | 10.40.150.0/24 | {"start": "10.40.150.10", "end": "10.40.150.253"} | | f8b5705f-a45e-4498-bea4-8c104a873fab | 17216200 | 172.16.200.0/24 | {"start": "172.16.200.11", "end": "172.16.200.253"} | +--------------------------------------+---------------------------------------------------+------------------+------------------------------------------------------+ 檢視17216150網段的詳情，看到它使用的DNS為114 [[email protected] ~]# neutron subnet-show 358321c0-6cbc-4ed7-a9e3-d8e7c3a6cf3a +-------------------+-----------------------------------------------------+ | Field | Value | +-------------------+-----------------------------------------------------+ | allocation_pools | {"start": "172.16.150.11", "end": "172.16.150.253"} | | cidr | 172.16.150.0/24 | | dns_nameservers | 114.114.114.114 | | enable_dhcp | True | | gateway_ip | | | host_routes | | | id | 358321c0-6cbc-4ed7-a9e3-d8e7c3a6cf3a | | ip_version | 4 | | ipv6_address_mode | | | ipv6_ra_mode | | | name | 17216150 | | network_id | 2b32fcf5-1db9-4972-a077-219d520624a3 | | subnetpool_id | | | tenant_id | 18649c1da2594d31988fd26baf15252b | +-------------------+-----------------------------------------------------+ 修改它的DNS位址iP。還支援優先級。這個操作是覆寫型的。 neutron subnet-update 358321c0-6cbc-4ed7-a9e3-d8e7c3a6cf3a --dns_nameservers list=true 10.40.200.100 114.114.114.114 Updated subnet: 358321c0-6cbc-4ed7-a9e3-d8e7c3a6cf3a [[email protected] ~]# neutron subnet-show 358321c0-6cbc-4ed7-a9e3-d8e7c3a6cf3a +-------------------+-----------------------------------------------------+ | Field | Value | +-------------------+-----------------------------------------------------+ | allocation_pools | {"start": "172.16.150.11", "end": "172.16.150.253"} | | cidr | 172.16.150.0/24 | | dns_nameservers | 10.40.200.100 | | | 114.114.114.114 | | enable_dhcp | True | | gateway_ip | | | host_routes | | | id | 358321c0-6cbc-4ed7-a9e3-d8e7c3a6cf3a | | ip_version | 4 | | ipv6_address_mode | | | ipv6_ra_mode | | | name | 17216150 | | network_id | 2b32fcf5-1db9-4972-a077-219d520624a3 | | subnetpool_id | | | tenant_id | 18649c1da2594d31988fd26baf15252b | +-------------------+-----------------------------------------------------+ 此操作是針對要建立和啟動的VM虛拟機有效，老的，已啟動的VM，預設不會修改，可通過配置管理工具，比如saltstack，将伺服器上的/etc/resolv.conf配置檔案進行批量修改，并實時生效。
轉載于:https://www.cnblogs.com/veniceslove/p/6289021.html
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