今天的笔记主要是关于Linux操作系统基础的相关知识。
网络管理
(1) 网络状态查看
在Linux中经常使用ifconfig，route和netstat查看网络状态，它们就是. net-tools工具，下面我来使用下。
我就说下ifconfig和route。
在我们的linux中有很多网卡接口，比如eth0第一块网卡网络接口，eno1板载⽹网卡， ens33 PCI-E⽹网卡 。CentOS 7 使⽤用了⼀致性⽹络设备命名，以上都不匹配，则使⽤ eth0
- [root@node01 ~]# ifconfig eth0
- eth0: error fetching interface information: Device not found
- [root@node01 ~]# ifconfig ens33
- ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
- inet 192.168.92.90 netmask 255.255.255.0 broadcast 192.168.92.255
- inet6 fe80::b889:1772:c306:ef8f prefixlen 64 scopeid 0x20<link>
- ether 00:0c:29:07:43:5a txqueuelen 1000 (Ethernet)
- RX packets 910 bytes 954985 (932.6 KiB)
- RX errors 0 dropped 0 overruns 0 frame 0
- TX packets 450 bytes 38942 (38.0 KiB)
- TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
(2) 网络配置文件
ifcfg-eth0，/etc/hosts
在配置hadoop，elasticsearch集群的时候需要在/etc/hosts配置集群IP和主机名，有时候你ping不了百度，可能域名解析不了，需要在/etc/sysconfig/network-scripts/ifcfg-eth0配置
- [root@node01 ~]# vim /etc/sysconfig/network
- #########
- HOSTNAME=node01
- [root@node01 ~]# vim /etc/hosts
- #########
- 192.168.92.90 node01
- 192.168.92.91 node02
- 192.168.92.92 node03
- [root@node01 ~]# 配置DNS，域名解析服务
- [root@node01 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
- DNS1=202.106.0.20
- DNS2=8.8.8.8
(3) 故障排除命令
第一，ping百度：查看目标机器的网络是否可通
- maoli@ubuntu:~$ ping baidu.com
- PING baidu.com (220.181.38.148) 56(84) bytes of data.
- 64 bytes from 220.181.38.148: icmp_seq=1 ttl=128 time=49.6 ms
- 64 bytes from 220.181.38.148: icmp_seq=2 ttl=128 time=48.2 ms
- ^C
- --- baidu.com ping statistics ---
- 2 packets transmitted, 2 received, 0% packet loss, time 1001ms
- rtt min/avg/max/mdev = 48.223/48.948/49.673/0.725 ms
traceroute
- nslookup：nslookup www.baidu.com Server即为域名对应的ip
- maoli@ubuntu:~$ nslookup www.baidu.com
- Server: 127.0.1.1
- Address: 127.0.1.1#53
- Non-authoritative answer:
- www.baidu.com canonical name = www.a.shifen.com.
- Name: www.a.shifen.com
- Address: 182.61.200.6
- Name: www.a.shifen.com
- Address: 182.61.200.7
- maoli@ubuntu:~$ sudo tcpdump -i any -n port 80 -n
- tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
- listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
- 10:28:11.003675 IP 192.168.92.1.53951 > 192.168.92.135.80: Flags [S], seq 185886164, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
- 10:28:11.003875 IP 192.168.92.135.80 > 192.168.92.1.53951: Flags [S.], seq 2863640054, ack 185886165, win 64240, options [mss 1460,nop,nop,sackOK,nop,wscale 7], length 0
- 10:28:11.004114 IP 192.168.92.1.53951 > 192.168.92.135.80: Flags [.], ack 1, win 4106, length 0
- 10:28:11.010472 IP 192.168.92.1.53951 > 192.168.92.135.80: Flags [P.], seq 1:476, ack 1, win 4106, length 475: HTTP: GET /sqli-labs/ HTTP/1.1
- maoli@ubuntu:~$ sudo netstat -ntlp
- 激活Internet连接 (仅服务器)
- Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
- tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1111/sshd
- tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 14200/cupsd
- tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 1148/mysqld
- tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN 1165/redis-server 1
- tcp 0 0 127.0.1.1:53 0.0.0.0:* LISTEN 1285/dnsmasq
- tcp6 0 0 :::22 :::* LISTEN 1111/sshd
- tcp6 0 0 ::1:631 :::* LISTEN 14200/cupsd
- tcp6 0 0 :::9000 :::* LISTEN 2234/docker-proxy
- tcp6 0 0 :::80 :::* LISTEN 1842/apache2
(4) 网络服务管理
⽹络服务管理程序分为两种，分别为SysV和systemd。现在Systemd已经基本取代了SysV的Init。
(5) 设置静态ip
在搭建任何集群，都是要设置静态ip的。
- [root@node01]# vim /etc/sysconfig/network-scripts/ifcfg-ens33
- ################
- BOOTPROTO=static
- ONBOOT="yes"
- # 网关地址根据系统的网络而定
- GATEWAY=192.168.92.2
- # 设置的静态ip
- IPADDR=192.168.92.92
- NETMASK=255.255.255.0
- # 配置DNS服务器
- DNS1=8.8.8.8
- DNS2=8.8.4.4
