http://cuidehua.blog.51cto.com/5449828/1788240
很多應用軟件會涉及到fqdn
如salt獲取到的fqnd和host可能會不一樣，兩者有何區別？
THE FQDN
You can’t change the FQDN (as returned by hostname --fqdn) or the DNS domain name (as returned by dnsdomainname) with this command. The FQDN of
the system is the name that the resolver(3) returns for the host name.
Technically: The FQDN is the name gethostbyname(2) returns for the host name returned by gethostname(2). The DNS domain name is the part after
the first dot.
Therefore it depends on the configuration (usually in /etc/host.conf) how you can change it. Usually (if the hosts file is parsed before DNS or
NIS) you can change it in /etc/hosts.
If a machine has multiple network interfaces/addresses or is used in a mobile environment, then it may either have multiple FQDNs/domain names or
none at all. Therefore avoid using hostname --fqdn, hostname --domain and dnsdomainname. hostname --ip-address is subject to the same limitations
so it should be avoided as well.
FQDN = 簡短的名字 + 域
如: hostname返回的結果是 dev-qa001 域為test.com 則fqdn為 dev-qa001.test.com
-f, --fqdn, --long
Display the FQDN (Fully Qualified Domain Name). A FQDN consists of a short host name and the DNS domain name. Unless you are using bind or
NIS for host lookups you can change the FQDN and the DNS domain name (which is part of the FQDN) in the /etc/hosts file. See the warnings in
section THE FQDN above, and avoid using this option; use hostname --all-fqdnsinstead.
返回hostname的命令
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hostname
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返回域的命令
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dnsdomainname
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返回fqdn的命令
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hostname
-f
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hostname
-f -
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可以查看解析的詳細過程
有時候這兩個還不一樣
hostname --all-fqdns 和 hostname -f
python中socket的庫 socket.getfqdn() 這個方法是調用 hostname --all-fqdsn哦！ salt中可能會有坑(注意 minion端的/etc/hosts文件)
如何設置fqdn
優先的方法，方法一 設置/etc/hosts
[root@CentOS-6-121 ~]# cat /etc/hosts | grep -i "Centos"
10.59.74.121 CentOS-6-121.test.com CentOS-6-121
第一列為IP 第二列為fqnd 第三列為主機名 (位置不能錯誤,否則結果不一致)
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[root@CentOS-6-121 ~]
# hostname
CentOS-6-121
[root@CentOS-6-121 ~]
# hostname -f
CentOS-6-121.
test
.com
[root@CentOS-6-121 ~]
# dnsdomainname
test
.com
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方法二：你配置了dns 通過dns查找
[root@CentOS-6-121 ~]# cat /etc/resolv.conf
search a.pa.com
但是你的dns一定要能解析你的fqdn,返回返回失效(你去除了hosts中的配置后)
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[root@CentOS-6-121 ~]
# hostname
CentOS-6-121
[root@CentOS-6-121 ~]
# dnsdomainname
dnsdomainname: Unknown host
[root@CentOS-6-121 ~]
# hostname -f
hostname
: Unknown host
[root@CentOS-6-121 ~]
#
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如果能解析,dnsdomainname 為你指定的search (可以指定多個，有一個成功能解析即可)
三: salt獲取fqdn的時候 經驗
通過minion端的salt-call -g 才是最准確的 和 python中的socket.getfqdn()
通過master端 salt "dev-qa008" grains.item fqdn 獲取到的可能不一致
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