當你有若幹個容器之後,你可能就希望實現容器的跨機部署訪問了,比如aspnetcore在一臺host上,mysql在另外一個host上,如果要實現這樣的功能,需要你 藉助docker自帶的overlay網路模型了。 一: overlay網路模型 要想快速的搭建overlay網路,你可以通過docker ...
當你有若幹個容器之後,你可能就希望實現容器的跨機部署訪問了,比如aspnetcore在一臺host上,mysql在另外一個host上,如果要實現這樣的功能,需要你
藉助docker自帶的overlay網路模型了。
一: overlay網路模型
要想快速的搭建overlay網路,你可以通過docker預設的swarm集群給你預設生成的名ingress的overlay網路,這樣會預設開放一些埠供底層機器內的訪問,比如:
UDP 4789 是用於overlay network 流量傳輸的,作為開發角度,你只需要知道這是一個基於底層物理網路構建出的一個上層虛擬網路,而你的程式都是跑在這個虛擬網
絡上,如果要畫圖,大概就是這樣吧!
二:通過docker swarm構建overlay網路
為了構建overlay網路,需要備有兩台機器(使用虛擬機即可):
192.168.23.146 manager 192.168.23.147 worker
使用起來很簡單,在 146機器上執行 docker swarm init 初始化一個集群,同時預設了該機作為 cluster 的manager節點。
[root@manager ~]# docker swarm init Swarm initialized: current node (g0o8vkgzruv63hsx4pkjs0yfk) is now a manager. To add a worker to this swarm, run the following command: docker swarm join --token SWMTKN-1-0oxo6qrxwvl8xlneq0jqz2zd87nkj7c0vyf1h9m8kcj3qbzd4v-3eu9zb5athq0s2n79rncbejb1 192.168.23.146:2377 To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions. [root@manager ~]# docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION g0o8vkgzruv63hsx4pkjs0yfk * manager Ready Active Leader 18.09.6 [root@manager ~]#
當執行完init之後,通過node ls 可以看到,當前cluster集群中只有一個node節點,而且還是Leader,同時docker還告訴我們怎麼將其他node加入到集群中作為
worker節點,驗證方式是token,好了,那我可以將這段output copy到 147 的 shell上。
[root@worker ~]# docker swarm join --token SWMTKN-1-0oxo6qrxwvl8xlneq0jqz2zd87nkj7c0vyf1h9m8kcj3qbzd4v-3eu9zb5athq0s2n79rncbejb1 192.168.23.146:2377 This node joined a swarm as a worker.
最後通過在 146 上執行 docker node ls 看一下集群信息,可以看到146,147都在一個集群了。
[root@manager ~]# docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION g0o8vkgzruv63hsx4pkjs0yfk * manager Ready Active Leader 18.09.6 ojjngean30orjzswh72o25rsr worker Ready Active 18.09.6
接下來再看一下,4789埠是否開放了,同時看一下ingress的overlay是否開啟了,如下:
[root@manager ~]# docker network ls NETWORK ID NAME DRIVER SCOPE f5fbe8d71b5a bridge bridge local 91cfc77a3c7f docker_gwbridge bridge local ac4a48a43517 host host local 5eux1lz4yom7 ingress overlay swarm 02f9bfe179ca none null local [root@manager ~]# netstat -tlnpu Active Internet connections (only servers) 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 4854/sshd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 5523/master tcp6 0 0 :::2377 :::* LISTEN 6349/dockerd tcp6 0 0 :::7946 :::* LISTEN 6349/dockerd tcp6 0 0 :::22 :::* LISTEN 4854/sshd tcp6 0 0 ::1:25 :::* LISTEN 5523/master udp 0 0 0.0.0.0:47160 0.0.0.0:* 4549/avahi-daemon: udp 0 0 0.0.0.0:68 0.0.0.0:* 4649/dhclient udp 0 0 0.0.0.0:123 0.0.0.0:* 4555/chronyd udp 0 0 127.0.0.1:323 0.0.0.0:* 4555/chronyd udp 0 0 0.0.0.0:4789 0.0.0.0:* - udp 0 0 0.0.0.0:5353 0.0.0.0:* 4549/avahi-daemon: udp 0 0 0.0.0.0:26134 0.0.0.0:* 4649/dhclient udp6 0 0 :::123 :::* 4555/chronyd udp6 0 0 ::1:323 :::* 4555/chronyd udp6 0 0 :::47743 :::* 4649/dhclient udp6 0 0 :::7946 :::* 6349/dockerd
預設名為ingress 的overlay driver是預設是不支持standalone容器加入的,所以我需要重新new一個overlay,並設置一下允許standalone容器加入此網路,好了,
說乾就乾,new了一個 test-net的overlay網路,通過--attachable 開啟附加功能。
[root@manager ~]# docker network create --driver=overlay --attachable test-net dajh2glpfattdnq2ahqchlhur [root@manager ~]# docker network ls NETWORK ID NAME DRIVER SCOPE f5fbe8d71b5a bridge bridge local 91cfc77a3c7f docker_gwbridge bridge local ac4a48a43517 host host local 5eux1lz4yom7 ingress overlay swarm 02f9bfe179ca none null local dajh2glpfatt test-net overlay swarm
三:python 跨機連接 redis
我準備把redis放在147機器上, python application 放在 146上,python 通過 對方的容器名(some-redis) 進行連接,如下圖所示:
1. 在147上執行docker run時附加 network 為指定的 test-net 網路
[root@worker ~]# docker run --network test-net --name some-redis -d redis
eca08e67e35160661e090ca42a61dacaee5dd8ca99f8e9c25e59ae6927d66328
2. python應用程式
主要有三個部分,app.py, Dockerfile, requirements.txt。
《1》 app.py
下麵要註意的是,在redis的構造函數中指定了host= some-redis ,也就是 147啟動容器名。
from flask import Flask from redis import Redis, RedisError import os import socket # Connect to Redis redis = Redis(host="some-redis", db=0, socket_connect_timeout=2, socket_timeout=2) app = Flask(__name__) @app.route("/") def hello(): try: visits = redis.incr("counter") except RedisError: visits = "<i>cannot connect to Redis, counter disabled</i>" html = "<b>Hostname:</b> {hostname}<br/>" \ "<b>Visits:</b> {visits}" return html.format(hostname=socket.gethostname(), visits=visits) if __name__ == "__main__": app.run(host='0.0.0.0', port=80)
《2》 Flask 和 Redis 依賴包 (requirements.txt)
Flask
Redis
《3》 最後就是dockerfile
FROM python:2.7-slim WORKDIR /app COPY . . EXPOSE 80 RUN pip install --trusted-host pypi.python.org -r requirements.txt VOLUME [ "/app" ] CMD [ "python", "app.py" ]
有了這三個,接下來就可以構建image了。
[root@manager app]# docker build -t pyweb:v1 . Sending build context to Docker daemon 4.608kB Step 1/7 : FROM python:2.7-slim 2.7-slim: Pulling from library/python fc7181108d40: Already exists 8c60b810a35a: Pull complete d207b275197c: Pull complete 63184f224d60: Pull complete Digest: sha256:1405fa2f8e9a232e2f60cafbb2b06ca2f1e0f577f4b4c397c361d6dba59fd24e Status: Downloaded newer image for python:2.7-slim ---> ca96bab3e2aa Step 2/7 : WORKDIR /app ---> Running in 6b8324c10dc0 Removing intermediate container 6b8324c10dc0 ---> a85fb403c57b Step 3/7 : COPY . . ---> f13015df5bf7 Step 4/7 : EXPOSE 80 ---> Running in 408a718df2b4 Removing intermediate container 408a718df2b4 ---> 39d30c3a092d Step 5/7 : RUN pip install --trusted-host pypi.python.org -r requirements.txt ---> Running in 0ee0982739d5 DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. Collecting Flask (from -r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/c3/31/6904ac846fc65a7fa6cac8b4ddc392ce96ca08ee67b0f97854e9575bbb26/Flask-1.1.0-py2.py3-none-any.whl (94kB) Collecting Redis (from -r requirements.txt (line 2)) Downloading https://files.pythonhosted.org/packages/ac/a7/cff10cc5f1180834a3ed564d148fb4329c989cbb1f2e196fc9a10fa07072/redis-3.2.1-py2.py3-none-any.whl (65kB) Collecting Jinja2>=2.10.1 (from Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/1d/e7/fd8b501e7a6dfe492a433deb7b9d833d39ca74916fa8bc63dd1a4947a671/Jinja2-2.10.1-py2.py3-none-any.whl (124kB) Collecting click>=5.1 (from Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/fa/37/45185cb5abbc30d7257104c434fe0b07e5a195a6847506c074527aa599ec/Click-7.0-py2.py3-none-any.whl (81kB) Collecting Werkzeug>=0.15 (from Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/9f/57/92a497e38161ce40606c27a86759c6b92dd34fcdb33f64171ec559257c02/Werkzeug-0.15.4-py2.py3-none-any.whl (327kB) Collecting itsdangerous>=0.24 (from Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/76/ae/44b03b253d6fade317f32c24d100b3b35c2239807046a4c953c7b89fa49e/itsdangerous-1.1.0-py2.py3-none-any.whl Collecting MarkupSafe>=0.23 (from Jinja2>=2.10.1->Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/fb/40/f3adb7cf24a8012813c5edb20329eb22d5d8e2a0ecf73d21d6b85865da11/MarkupSafe-1.1.1-cp27-cp27mu-manylinux1_x86_64.whl Installing collected packages: MarkupSafe, Jinja2, click, Werkzeug, itsdangerous, Flask, Redis Successfully installed Flask-1.1.0 Jinja2-2.10.1 MarkupSafe-1.1.1 Redis-3.2.1 Werkzeug-0.15.4 click-7.0 itsdangerous-1.1.0 Removing intermediate container 0ee0982739d5 ---> 704e7d655494 Step 6/7 : VOLUME [ "/app" ] ---> Running in 0c4ad68db249 Removing intermediate container 0c4ad68db249 ---> 5b0ce6eef187 Step 7/7 : CMD [ "python", "app.py" ] ---> Running in 388d972cbd6d Removing intermediate container 388d972cbd6d ---> fd7a0ffca7fc Successfully built fd7a0ffca7fc Successfully tagged pyweb:v1 [root@manager app]# docker run -d --network test-net -p 80:80 -v /app:/app --name pyapp pyweb:v1 9d419507b00adddd003f8e45580ec1ee48d4a0347091b65da1bc183a8bbe1dc2 [root@manager app]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 9d419507b00a pyweb:v1 "python app.py" 4 seconds ago Up 2 seconds 0.0.0.0:80->80/tcp pyapp [root@manager app]#
然後訪問一下 http://192.168.23.146,每刷新一下page,都會執行一次redis.incr操作。,這樣就實現了多容器之間的跨機器訪問,大家也可以把這些放到
docker-compose文件中哦。
好了,本篇就說到這裡,希望對你有幫助。