练习二：获取容器日志并对容器进行监控¶

01. 使用docker logs -f获取容器日志实时输出¶

使用以下命令链接到之前创建的docker-machine上，并针对php-webapp:1这个容器执行docker logs -f {容器id}命令，然后你可以使用浏览器刷新这个应用并看到日志的实时输出。

D:\docker-training
λ @FOR /f "tokens=*" %i IN ('docker-machine env {主机名称}') DO @%i

D:\docker-training
λ docker ps
CONTAINER ID        IMAGE                                        COMMAND                  CREATED             STATUS              PORTS
NAMES
2d6d22b5aa93        harbor.devopshub.cn/google/cadvisor:latest   "/usr/bin/cadvisor..."   7 minutes ago       Up 7 minutes        0.0.0.0:8080->8080/tcp
cadvisor
34f7b90869cb        localhost:5000/php-webapp:1                  "apache2-foreground"     About an hour ago   Up About an hour    0.0.0.0:81->80/tcp
sleepy_heyrovsky
95488ebcbeba        harbor.devopshub.cn/library/registry         "/entrypoint.sh /e..."   2 hours ago         Up 2 hours          0.0.0.0:5000->5000/tcp
agitated_galileo
c369822797c6        harbor.devopshub.cn/library/nginx            "nginx -g 'daemon ..."   2 hours ago         Up 2 hours          0.0.0.0:80->80/tcp, 443/tcp
elated_pasteur

D:\docker-training
λ docker logs -f 34f7
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.4. Set the 'ServerName' directive globally to suppress this message
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.4. Set the 'ServerName' directive globally to suppress this message
[Mon Dec 12 13:47:44.156252 2016] [mpm_prefork:notice] [pid 1] AH00163: Apache/2.4.10 (Debian) PHP/7.0.13 configured -- resuming normal operations
[Mon Dec 12 13:47:44.156480 2016] [core:notice] [pid 1] AH00094: Command line: 'apache2 -D FOREGROUND'
114.242.250.8 - - [12/Dec/2016:13:48:24 +0000] "GET / HTTP/1.1" 200 393 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36"

02. 使用google/cAdvisor对容器主机和应用进行监控¶

在以上主机中运行如下命令部署google/cadvisor

D:\docker-training\
λ docker run --volume=/:/rootfs:ro --volume=/var/run:/var/run:rw --volume=/sys:/sys:ro --volume=/var/lib/docker/:/var/lib/docker:ro --publish=8080:8080 --deta ch=true --name=cadvisor harbor.devopshub.cn/google/cadvisor:latest
time="2016-12-12T23:35:25+08:00" level=warning msg="Unable to use system certificate pool: crypto/x509: system root pool is not available on Windows"
Unable to find image 'harbor.devopshub.cn/google/cadvisor:latest' locally
latest: Pulling from google/cadvisor
e110a4a17941: Pull complete
e17fa94aae07: Pull complete
cb2aa9e31624: Pull complete
Digest: sha256:902449e23fc2cab1ca9788e2610b0928f27ee91e503f3326c7a463fa17d11dd9
Status: Downloaded newer image for harbor.devopshub.cn/google/cadvisor:latest
2d6d22b5aa9313382b9d63cbc3ab884b33acbb96cf21353169bfbcc1b892665b

部署完成后，使用浏览器导航到 http://{主机ip}:8080 ，可以看到如下页面，尝试对这台主机进行一些操作，如拉取镜像，启动和停止容器，可以看到监控数据的实时变化。

小结¶

至此，我们对如何监控容器环境进行了简单介绍。当前业界对容器监控的方案很多，大多数都是采用采集日志，并通过日志分析的方式来进行的。掌握获取容器内应用日志的方式是进行这些监控的基础。