Use user-defined bridge networks
Hai semuanya, sebelumnya kita udah mempelajari tentang default bridge network selanjutnya kita bahas tentang user-defined bridge network, Diantaranya meliputi:
- Management Docker Network
- Create multiple containers in same user-defined bridge network and how to connected each other
- Cleanup
Management Docker Network
Untuk me-manage Docker Network kita bisa menggunakan perintah docker network COMMAND. Untuk lebih detailnya kita bisa lihat dokumentasinya.
Jika dijalankan maka hasilnya seperti berikut:
➜ ~ docker network --help
Usage: docker network COMMAND
Manage networks
Commands:
connect Connect a container to a network
create Create a network
disconnect Disconnect a container from a network
inspect Display detailed information on one or more networks
ls List networks
prune Remove all unused networks
rm Remove one or more networks
Run 'docker network COMMAND --help' for more information on a command.
Untuk melihat daftar network kita bisa menggunakan perintah
Jika dijalankan maka hasilnya seperti berikut:
➜ ~ docker network ls
NETWORK ID NAME DRIVER SCOPE
a1dd8d92c317 bridge bridge local
9b4dac4a1f4a host host local
de6461398e10 none null local
Untuk melihat detail dari suatu network, kita bisa menggunakan perintah seperti berikut:
Jika di jalankan maka hasilnya seperti berikut:
➜ ~ docker network inspect bridge host none
[
{
"Name": "bridge",
"Id": "a1dd8d92c317716fefc26c1210a0e1cb280a0f695adeb7b7784effeeef0adec8",
"Created": "2021-05-26T00:47:45.778658Z",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "172.17.0.0/16",
"Gateway": "172.17.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {},
"Options": {
"com.docker.network.bridge.default_bridge": "true",
"com.docker.network.bridge.enable_icc": "true",
"com.docker.network.bridge.enable_ip_masquerade": "true",
"com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
"com.docker.network.bridge.name": "docker0",
"com.docker.network.driver.mtu": "1500"
},
"Labels": {}
},
{
"Name": "host",
"Id": "9b4dac4a1f4a86872ce14166d700a24d3a311a13b9b88df0e84adc76fcf06779",
"Created": "2021-04-03T10:50:17.4124317Z",
"Scope": "local",
"Driver": "host",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": []
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {},
"Options": {},
"Labels": {}
},
{
"Name": "none",
"Id": "de6461398e1002dba5d8d934ec95e77f55de36f3c2dc08a0f982d81eede35e70",
"Created": "2021-04-03T10:50:17.3972092Z",
"Scope": "local",
"Driver": "null",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": []
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {},
"Options": {},
"Labels": {}
}
]
Dari daftar network tersebut, yang dibuat oleh docker ketika kita meng-install Docker Engine. kita tidak bisa menghapus default atau pre-defined network.
Ok, sekarang untuk mencoba user-defined bridge network. Kita akan buat network dengan perintah seperti berikut:
For Bash script:
For Powershell script:
Jika dijalankan maka hasilnya seperti berikut:
➜ ~ docker network create backend_bridge `
>> --driver bridge
08ef47d6ea7a0011da3d85138e20e4a03f79bbf81b2bbc1433f8561136d4c672
➜ ~ docker network ls -f 'driver=bridge'
NETWORK ID NAME DRIVER SCOPE
08ef47d6ea7a backend_bridge bridge local
a1dd8d92c317 bridge bridge local
~ docker network inspect backend_bridge bridge -f '{{ .Name }} -> {{json .IPAM }}'
backend_bridge -> {"Driver":"default","Options":{},"Config":[{"Subnet":"172.21.0.0/16","Gateway":"172.21.0.1"}]}
bridge -> {"Driver":"default","Options":null,"Config":[{"Subnet":"172.17.0.0/16","Gateway":"172.17.0.1"}]}
How to connect containers each other in user-defined bridge network
For Bash script:
For Powershell script:
Jika di jalankan maka hasilnya seperti berikut:
➜ ~ docker container run `
>> --name webapp `
>> -p 8080:80 `
>> --network backend_bridge `
>> -d nginx `
>> | `
>> docker container run `
>> --name postgresdb `
>> -e POSTGRES_PASSWORD=password `
>> -p 5432:5432 `
>> --network backend_bridge `
>> -d postgres:12.6 `
>> | `
>> docker container run `
>> --name centos7 `
>> --network backend_bridge `
>> -it `
>> -d centos:7 bash
c374148946e8c5c073e5c11e0c75c4457f99c7aeaa8bcfdb9572072f8a16032f
➜ ~ docker container ls
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c374148946e8 centos:7 "bash" 15 seconds ago Up 14 seconds centos7
a22ff7c66400 postgres:12.6 "docker-entrypoint.s…" 16 seconds ago Up 14 seconds 0.0.0.0:5432->5432/tcp, :::5432->5432/tcp postgresdb
8b756747082e nginx "/docker-entrypoint.…" 17 seconds ago Up 16 seconds 0.0.0.0:8080->80/tcp, :::8080->80/tcp webapp
➜ ~ docker network inspect bridge backend_bridge --format '{{ .Name }} ==> {{json .Containers}}'
bridge ==> {}
backend_bridge ==>
{
"08d9210b39c8f78296a10ab5ea4c00d6a5d705ef689575057a5f3ed960a7a762":{
"Name":"postgresdb",
"EndpointID":"8b220c8947d5e6fc4ec5e353963b948a0b815b6c8827ecbfac2341f9139b5b89",
"MacAddress":"02:42:ac:15:00:03",
"IPv4Address":"172.21.0.3/16",
"IPv6Address":""
},
"d9a000b91856d10c84de4fd24079241deb7249f152f7f858b9b8f6ca4d9141ac":{
"Name":"webapp",
"EndpointID":"411c23b907e75f54be1abe44e961653bc81dfbe9092d8932dfd75e2317ea89df",
"MacAddress":"02:42:ac:15:00:04",
"IPv4Address":"172.21.0.4/16",
"IPv6Address":""
},
"e4f9e041acf0a89c44f1849e55d4b55bee86d628822b2c099470709b1163a4dd":{
"Name":"centos7",
"EndpointID":"7c345d7dc17c76dc1c8d4bf32ee05f6a2b8064d0568ed058c8ecc089454b2d5e",
"MacAddress":"02:42:ac:15:00:02",
"IPv4Address":"172.21.0.2/16",
"IPv6Address":""
}
}
Berbeda dengan default bridge network, pada user-defined bridge network jika suatu container mau komumikasi antara container maka kita bisa panggil dengan Internal IP-Address atau Container Name. Ok kita coba berikut schenarionya:
➜ ~ docker exec -it centos7 bash
[root@e4f9e041acf0 /]# ping -c 2 webapp
PING webapp (172.21.0.4) 56(84) bytes of data.
64 bytes from webapp.backend_bridge (172.21.0.4): icmp_seq=1 ttl=64 time=0.030 ms
64 bytes from webapp.backend_bridge (172.21.0.4): icmp_seq=2 ttl=64 time=0.038 ms
--- webapp ping statistics ---
[root@e4f9e041acf0 /]# curl webapp
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
[root@e4f9e041acf0 /]# ping -c 2 postgresdb
PING postgresdb (172.21.0.3) 56(84) bytes of data.
64 bytes from postgresdb.backend_bridge (172.21.0.3): icmp_seq=1 ttl=64 time=0.078 ms
64 bytes from postgresdb.backend_bridge (172.21.0.3): icmp_seq=2 ttl=64 time=0.038 ms
--- postgresdb ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1037ms
rtt min/avg/max/mdev = 0.038/0.058/0.078/0.020 ms
[root@e4f9e041acf0 /]# yum install postgresql -y
Installed:
postgresql.x86_64 0:9.2.24-6.el7_9
[root@e4f9e041acf0 /]# psql -h postgresdb -U postgres -W
Password for user postgres:
psql (9.2.24, server 12.6 (Debian 12.6-1.pgdg100+1))
WARNING: psql version 9.2, server version 12.0.
Some psql features might not work.
Type "help" for help.
postgres=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+------------+------------+-----------------------
postgres | postgres | UTF8 | en_US.utf8 | en_US.utf8 |
template0 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | =c/postgres +
| | | | | postgres=CTc/postgres
(3 rows)
postgres=# select 1 + 2 as tambah;
tambah
--------
3
(1 row)
postgres=# \q
[root@e4f9e041acf0 /]# exit
➜ ~ docker container inspect webapp -f '{{json .NetworkSettings.Networks }}'
{
"backend_bridge":{
"IPAMConfig":{
},
"Links":null,
"Aliases":[
"d9a000b91856"
],
"NetworkID":"08ef47d6ea7a0011da3d85138e20e4a03f79bbf81b2bbc1433f8561136d4c672",
"EndpointID":"3e27239464a83dae36332b327fb72292a1bdcd9190f9fcc06d41685f378cefe7",
"Gateway":"172.21.0.1",
"IPAddress":"172.21.0.4",
"IPPrefixLen":16,
"IPv6Gateway":"",
"GlobalIPv6Address":"",
"GlobalIPv6PrefixLen":0,
"MacAddress":"02:42:ac:15:00:04",
"DriverOpts":{
}
}
}
➜ ~ docker network disconnect backend_bridge webapp
➜ ~ docker network inspect backend_bridge --format '{{json .Containers }}'
{
"08d9210b39c8f78296a10ab5ea4c00d6a5d705ef689575057a5f3ed960a7a762":{
"Name":"postgresdb",
"EndpointID":"8b220c8947d5e6fc4ec5e353963b948a0b815b6c8827ecbfac2341f9139b5b89",
"MacAddress":"02:42:ac:15:00:03",
"IPv4Address":"172.21.0.3/16",
"IPv6Address":""
},
"e4f9e041acf0a89c44f1849e55d4b55bee86d628822b2c099470709b1163a4dd":{
"Name":"centos7",
"EndpointID":"7c345d7dc17c76dc1c8d4bf32ee05f6a2b8064d0568ed058c8ecc089454b2d5e",
"MacAddress":"02:42:ac:15:00:02",
"IPv4Address":"172.21.0.2/16",
"IPv6Address":""
}
}
➜ ~ docker container inspect webapp -f '{{json .NetworkSettings.Networks }}'
{}
➜ ~ docker exec -it centos7 bash
[root@e4f9e041acf0 /]# ping -c 2 webapp
ping: webapp: Name or service not known
[root@e4f9e041acf0 /]# curl webapp
curl: (6) Could not resolve host: webapp; Unknown error
➜ ~ docker exec -it centos7 bash
[root@e4f9e041acf0 /]# ping -c 2 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=37 time=22.1 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=37 time=21.6 ms
--- 8.8.8.8 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
[root@e4f9e041acf0 /]# exit
Cleanup
Setelah kita mencoba, saatnya kita bersih-bersih dulu. Berikut adalah perintahnya:
For Bash script:
For Powershell script:
the conclusion
Bridge networks are isolated networks on a single Engine installation. Differences between user-defined bridges and the default bridge:
- User-defined bridges provide automatic DNS resolution between containers.
- User-defined bridges provide better isolation.
- Containers can be attached and detached from user-defined networks on the fly.
- Each user-defined network creates a configurable bridge.
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