PowerFlex 4.x DNS 서버를 업데이트하는 방법

1. MVM 노드에서 다음 명령을 실행하여 현재 DNS 서버를 확인합니다.

cat /etc/resolv.conf

delladmin@mvm1:~> cat /etc/resolv.conf
### /etc/resolv.conf is a symlink to /run/netconfig/resolv.conf
### autogenerated by netconfig!
#
# Before you change this file manually, consider to define the
# static DNS configuration using the following variables in the
# /etc/sysconfig/network/config file:
#     NETCONFIG_DNS_STATIC_SEARCHLIST
#     NETCONFIG_DNS_STATIC_SERVERS
#     NETCONFIG_DNS_FORWARDER
# or disable DNS configuration updates via netconfig by setting:
#     NETCONFIG_DNS_POLICY=''
#
# See also the netconfig(8) manual page and other documentation.
#
### Call "netconfig update -f" to force adjusting of /etc/resolv.conf.
search boston.ee.com
nameserver 1.2.3.4  <----

2. MVM 노드에서 DNS 서버를 추가/제거하려면 /etc/sysconfig/network/config 파일의 NETCONFIG_DNS_STATIC_SERVERS 섹션을 편집합니다.

아래 예에서는 DNS 서버 5.6.7.8이 추가됩니다. 파일을 저장하고 필요한 내용을 변경한 후 종료합니다.

sudo vi /etc/sysconfig/network/config

delladmin@mvm1:~> sudo vi /etc/sysconfig/network/config
...
## Type:        string
## Default:     ""
#
# List of DNS nameserver IP addresses to use for host-name lookup.
# When the NETCONFIG_DNS_FORWARDER variable is set to "resolver",
# the name servers are written directly to /etc/resolv.conf.
# Otherwise, the nameserver are written into a forwarder specific
# configuration file and the /etc/resolv.conf does not contain any
# nameservers causing the glibc to use the name server on the local
# machine (the forwarder). See also netconfig(8) manual page.
#
NETCONFIG_DNS_STATIC_SERVERS="1.2.3.4 5.6.7.8"  <----

3. 다음 명령을 실행하여 변경 사항을 /etc/resolv.conf로 푸시합니다.

sudo netconfig update -f

delladmin@mvm1:~> sudo netconfig update -f

4. 변경 사항이 적용되었는지 확인합니다.

delladmin@mvm1:~> cat /etc/resolv.conf
 
### /etc/resolv.conf is a symlink to /run/netconfig/resolv.conf
### autogenerated by netconfig!
#
# Before you change this file manually, consider to define the
# static DNS configuration using the following variables in the
# /etc/sysconfig/network/config file:
#     NETCONFIG_DNS_STATIC_SEARCHLIST
#     NETCONFIG_DNS_STATIC_SERVERS
#     NETCONFIG_DNS_FORWARDER
# or disable DNS configuration updates via netconfig by setting:
#     NETCONFIG_DNS_POLICY=''
#
# See also the netconfig(8) manual page and other documentation.
#
### Call "netconfig update -f" to force adjusting of /etc/resolv.conf.
search boston.ee.com
nameserver 1.2.3.4
nameserver 5.6.7.8     <-----

5. 모든 MVM 노드에서 위의 단계를 반복합니다.

6. coredns 포드를 삭제하여 변경 사항을 해당 포드에 전파합니다.

for x in `kubectl get pods -n kube-system| grep -i rke2-coredns-rke2-coredns | awk '{print $1}' | grep -iv auto`; do kubectl delete pods -n kube-system $x; done

7. 이제 DNS 변경 사항이 coredns Pod에 반영되었는지 확인합니다(DNS를 담당하는 두 개의 coredns Pod가 있음).

for x in `kubectl get pods -n kube-system|grep -i rke2-coredns-rke2-coredns|awk '{print $1}'|grep -iv auto`; do echo $x; kubectl exec -it $x -n kube-system -- cat /etc/resolv.conf; echo " "; done
 

rke2-coredns-rke2-coredns-6d6fb45d66-8t962
search boston.ee.com
nameserver 1.2.3.4
nameserver 5.6.7.8     <-----
 
rke2-coredns-rke2-coredns-6d6fb45d66-b5c8f
search boston.ee.com
nameserver 1.2.3.4
nameserver 5.6.7.8     <-----