AWS EC2

AWS EC2 faq and some tips.

Time sync when security group deny all outbound

在關閉所有對外連線或沒有網際網路的狀況下，VM 會無法進行時間同步。 AWS 預留了一個 Link-local address 可在此情況下提供時間同步的服務。

Use chrony

1. Edit /etc/chrony.conf, and add following line.

/etc/chrony.conf

server 169.254.169.123 prefer iburst minpoll 4 maxpoll 4

2. Restart the chrony daemon (chronyd).

sudo service chronyd restart

3. Verify that chrony is using the 169.254.169.123 IP address to synchronize the time.

chronyc sources -v

Reference

• 正體中文： https://docs.aws.amazon.com/zh_tw/AWSEC2/latest/UserGuide/set-time.html
• English: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/set-time.html

Extend a Linux file system after resizing a volume

調整磁碟區大小後擴展 Linux 檔案系統，基本上非 EC2 環境，步驟也差不多。

Reference

• 正體中文： https://docs.aws.amazon.com/zh_tw/AWSEC2/latest/UserGuide/recognize-expanded-volume-linux.html
• English: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/recognize-expanded-volume-linux.html