CentOS常用指令

安裝

yum install 要裝的東西

網路相關工具 (檢查打開的port)

1	yum install net-tools

SSH Server (SSH 服務)

1	yum install openssh openssh-server

SSH Client (SSH Client)

1	yum install openssh-clients

firewall-cmd (設定防火牆)

1	sudo yum install firewalld

安裝可能會遇到的問題

failed to download metadata for repo…

因為CentOS7已經沒有維護了，要換一個下載套件的位置

sed -i ‘s/mirrorlist/#mirrorlist/g’ /etc/yum.repos.d/CentOS-*
sed -i ‘s|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g’ /etc/yum.repos.d/CentOS-*

Errors during downloading metadata for repository ‘appstream’…:

更新SSL憑證

1 2	curl http://www.example.com/ca/cacert.pem -o /etc/pki/tls/certs/ca-bundle.crt curl -v https://example.com

Failed to download metadata for repo ‘appstream’: Cannot download repomd.xml: Curl error (77): Problem with the SSL CA cert (path? access rights?) for …

關閉sslverify

1
2
3

vi /etc/yum.conf
增加內容
sslverify=false

System has not been booted with systemd as init system (PID 1). Can’t operate.Failed to connect to bus: Host is down

1.系統尚未使用systemd作為初始化系統重新啟動系統，檢查systemd有沒有安裝(yum install systemd)
2.如果訊息還是出現的話，切換初始化系統從舊的SysVinit到systemd

1	systemctl enable systemd

檢查目前已經裝的東西

rpm -q 套件名稱

1	rpm -q openssh-server

啟動服務

啟動SSH SERVER

1	systemctl start sshd

開機啟動服務

啟動SSH SERVER

1	systemctl enable sshd

查目前IP

1
2

ip a
ip r

clear screen

ctrl+L

列出目前有開的所有port

1 2	(需要安裝套件net-tools : yum install net-tools) netstat -tlnp

防火牆設定

打開某個port(–permanent 永久設定開啟，否則防火牆重啟或是重新設定時會失效)

1	firewall-cmd --permanent --zone=public --add-port=22/tcp

檢查防火牆目前打開port狀態

1	firewall-cmd --zone=public --list-all

重新讀取防火牆設定

1	firewall-cmd --reload

檢查打開的port設定是否有被加入防火牆設定

1	firewall-cmd --zone=public --list-all

SSH連線到某台機器

1 2	ssh 帳號@ip ssh root@123.456.789

ping 某台機器確定是否可以連線

1 2	ping ip ping 123.456.789

sudo command not found

1.檢查sudoers.d是否存在

1	find /etc/suders.d

如果不存在的話安裝sudo

1	yum install sudo

不回應Ping

sudo vi /proc/sys/net/ipv4/icmp_echo_ignore_all
1 不回應ICMP請求
0 回應ICMP請求

docker取的container ip

查container id

1	docker ps --format "table {{.ID}}\t{{.Status}}\t{{.Names}}"

查指定container ip

1	docker inspect -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' container_id

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