对于运行在Docker环境的容器，有时我们想查询它们的一些基本信息，例如环境变量、hostname、ip地址等，接下来我们以一个tomcat容器为例，看看有哪些方式来取得这些信息；
原文地址：https://blog.csdn.net/boling_cavalry/article/details/80215214
创建tomcat容器
在docker环境下执行如下命令，即可创建一个名为tomcat001的tomcat容器：
docker run --name tomcat001 -idt tomcat执行docker ps检查一下，容器创建成功：
root@maven:~# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
98d119ed4c73 tomcat "catalina.sh run" 10 minutes ago Up 10 minutes 8080/tcp tomcat001获取信息常用的方式有如下三种：
1. 进入容器内部获取信息；
2. 执行docker exec命令；
3. 执行docker inspect -f命令（推荐方式）；
第一种：进入容器内部获取信息
执行以下命令可进入容器内部：
docker exec -it tomcat001 /bin/bash此时已进入容器内部，所以分别执行hostname、ip addr、env这三个命令可以获取相关信息，如下：
root@98d119ed4c73:/usr/local/tomcat# hostname
98d119ed4c73
root@98d119ed4c73:/usr/local/tomcat# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
17: eth0@if18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
link/ether 02:42:ac:11:00:05 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet 172.17.0.5/16 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::42:acff:fe11:5/64 scope link
valid_lft forever preferred_lft forever
root@98d119ed4c73:/usr/local/tomcat# env
LD_LIBRARY_PATH=/usr/local/tomcat/native-jni-lib
CATALINA_HOME=/usr/local/tomcat
LANG=C.UTF-8
HOSTNAME=98d119ed4c73
OPENSSL_VERSION=1.1.0f-3+deb9u1
TOMCAT_VERSION=8.5.24
GPG_KEYS=05AB33110949707C93A279E3D3EFE6B686867BA6 07E48665A34DCAFAE522E5E6266191C37C037D42 47309207D818FFD8DCD3F83F1931D684307A10A5 541FBE7D8F78B25E055DDEE13C370389288584E7 61B832AC2F1C5A90F0F9B00A1C506407564C17A3 713DA88BE50911535FE716F5208B0AB1D63011C7 79F7026C690BAA50B92CD8B66A3AD3F4F22C4FED 9BA44C2621385CB966EBA586F72C284D731FABEE A27677289986DB50844682F8ACB77FC2E86E29AC A9C5DF4D22E99998D9875A5110C01C5A2F6059E7 DCFD35E0BF8CA7344752DE8B6FB21E8933C60243 F3A04C595DB5B6A5F1ECA43E3B7BBB100D811BBE F7DA48BB64BCB84ECBA7EE6935CD23C10D498E23
JAVA_HOME=/docker-java-home/jre
TOMCAT_NATIVE_LIBDIR=/usr/local/tomcat/native-jni-lib
JAVA_VERSION=8u151
PWD=/usr/local/tomcat
HOME=/root
CA_CERTIFICATES_JAVA_VERSION=20170531+nmu1
TOMCAT_MAJOR=8
JAVA_DEBIAN_VERSION=8u151-b12-1~deb9u1
TOMCAT_SHA1=9e26ba61c5665aafc849073edeb769be555283cd
TERM=xterm
SHLVL=1
TOMCAT_ASC_URLS=https://www.apache.org/dyn/closer.cgi?action=download&filename=tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc https://www-us.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc https://www.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc https://archive.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc
PATH=/usr/local/tomcat/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
TOMCAT_TGZ_URLS=https://www.apache.org/dyn/closer.cgi?action=download&filename=tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz https://www-us.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz https://www.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz https://archive.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz
_=/usr/bin/env第二种：执行docker exec命令
不用进入容器，直接在docker环境执行docker exec 容器名 容器内命令的方式也可以获取相关信息，举例如下：
1. 获取容器的hostname：docker exec tomcat001 hostname
2. 获取容器ip地址：docker exec tomcat001 ip addr
3. 获取容器环境变量：docker exec tomcat001 env
执行结果如下所示:
root@maven:~# docker exec tomcat001 hostname
98d119ed4c73
root@maven:~# docker exec tomcat001 ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
17: eth0@if18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
link/ether 02:42:ac:11:00:05 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet 172.17.0.5/16 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::42:acff:fe11:5/64 scope link
valid_lft forever preferred_lft forever
root@maven:~# docker exec tomcat001 env
PATH=/usr/local/tomcat/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=98d119ed4c73
LANG=C.UTF-8
JAVA_HOME=/docker-java-home/jre
JAVA_VERSION=8u151
JAVA_DEBIAN_VERSION=8u151-b12-1~deb9u1
CA_CERTIFICATES_JAVA_VERSION=20170531+nmu1
CATALINA_HOME=/usr/local/tomcat
TOMCAT_NATIVE_LIBDIR=/usr/local/tomcat/native-jni-lib
LD_LIBRARY_PATH=/usr/local/tomcat/native-jni-lib
OPENSSL_VERSION=1.1.0f-3+deb9u1
GPG_KEYS=05AB33110949707C93A279E3D3EFE6B686867BA6 07E48665A34DCAFAE522E5E6266191C37C037D42 47309207D818FFD8DCD3F83F1931D684307A10A5 541FBE7D8F78B25E055DDEE13C370389288584E7 61B832AC2F1C5A90F0F9B00A1C506407564C17A3 713DA88BE50911535FE716F5208B0AB1D63011C7 79F7026C690BAA50B92CD8B66A3AD3F4F22C4FED 9BA44C2621385CB966EBA586F72C284D731FABEE A27677289986DB50844682F8ACB77FC2E86E29AC A9C5DF4D22E99998D9875A5110C01C5A2F6059E7 DCFD35E0BF8CA7344752DE8B6FB21E8933C60243 F3A04C595DB5B6A5F1ECA43E3B7BBB100D811BBE F7DA48BB64BCB84ECBA7EE6935CD23C10D498E23
TOMCAT_MAJOR=8
TOMCAT_VERSION=8.5.24
TOMCAT_SHA1=9e26ba61c5665aafc849073edeb769be555283cd
TOMCAT_TGZ_URLS=https://www.apache.org/dyn/closer.cgi?action=download&filename=tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz https://www-us.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz https://www.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz https://archive.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz
TOMCAT_ASC_URLS=https://www.apache.org/dyn/closer.cgi?action=download&filename=tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc https://www-us.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc https://www.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc https://archive.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc
HOME=/root第三种：使用docker inspect命令
推荐使用docker inspect来获取信息，这个命令会返回一个json字符串，里面以key-value的格式准备了该容器相关的信息，内容十分丰富，可以一次性取得全部内容，也可以返回指定key对应的信息；
我们先来看看所有内容，执行命令docker inspect tomcat001，可以看到如下信息：
root@maven:~# docker inspect tomcat001
[
{
"Id": "98d119ed4c73c750e53353e77f7c6942803809a9d5dedc28d8b0f41ce58b8b17",
"Created": "2018-05-06T07:39:45.464492435Z",
"Path": "catalina.sh",
"Args": [
"run"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 22468,
"ExitCode": 0,
"Error": "",
"StartedAt": "2018-05-06T07:39:46.143092505Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "sha256:3dcfe809147daf54fbdbe1f6886b4c49df63f28e2b3c8ac119fef6a7f7490d3c",
"ResolvConfPath": "/var/lib/docker/containers/98d119ed4c73c750e53353e77f7c6942803809a9d5dedc28d8b0f41ce58b8b17/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/98d119ed4c73c750e53353e77f7c6942803809a9d5dedc28d8b0f41ce58b8b17/hostname",
"HostsPath": "/var/lib/docker/containers/98d119ed4c73c750e53353e77f7c6942803809a9d5dedc28d8b0f41ce58b8b17/hosts",
"LogPath": "/var/lib/docker/containers/98d119ed4c73c750e53353e77f7c6942803809a9d5dedc28d8b0f41ce58b8b17/98d119ed4c73c750e53353e77f7c6942803809a9d5dedc28d8b0f41ce58b8b17-json.log",
"Name": "/tomcat001",
"RestartCount": 0,
"Driver": "aufs",
"MountLabel": "",
"ProcessLabel": "",
"AppArmorProfile": "",
"ExecIDs": [
"cffec99f38514024f6a6e31e0e160d37d295041e4813a2245466be2dbc9c4037"
],
"HostConfig": {
"Binds": null,
"ContainerIDFile": "",
"LogConfig": {
"Type": "json-file",
"Config": {}
},
"NetworkMode": "default",
"PortBindings": {},
"RestartPolicy": {
"Name": "no",
"MaximumRetryCount": 0
},
"AutoRemove": false,
"VolumeDriver": "",
"VolumesFrom": null,
"CapAdd": null,
"CapDrop": null,
"Dns": [],
"DnsOptions": [],
"DnsSearch": [],
"ExtraHosts": null,
"GroupAdd": null,
"IpcMode": "",
"Cgroup": "",
"Links": null,
"OomScoreAdj": 0,
"PidMode": "",
"Privileged": false,
"PublishAllPorts": false,
"ReadonlyRootfs": false,
"SecurityOpt": null,
"UTSMode": "",
"UsernsMode": "",
"ShmSize": 67108864,
"Runtime": "runc",
"ConsoleSize": [
0,
0
],
"Isolation": "",
"CpuShares": 0,
"Memory": 0,
"NanoCpus": 0,
"CgroupParent": "",
"BlkioWeight": 0,
"BlkioWeightDevice": null,
"BlkioDeviceReadBps": null,
"BlkioDeviceWriteBps": null,
"BlkioDeviceReadIOps": null,
"BlkioDeviceWriteIOps": null,
"CpuPeriod": 0,
"CpuQuota": 0,
"CpuRealtimePeriod": 0,
"CpuRealtimeRuntime": 0,
"CpusetCpus": "",
"CpusetMems": "",
"Devices": [],
"DiskQuota": 0,
"KernelMemory": 0,
"MemoryReservation": 0,
"MemorySwap": 0,
"MemorySwappiness": -1,
"OomKillDisable": false,
"PidsLimit": 0,
"Ulimits": null,
"CpuCount": 0,
"CpuPercent": 0,
"IOMaximumIOps": 0,
"IOMaximumBandwidth": 0
},
"GraphDriver": {
"Name": "aufs",
"Data": null
},
"Mounts": [],
"Config": {
"Hostname": "98d119ed4c73",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"ExposedPorts": {
"8080/tcp": {}
},
"Tty": true,
"OpenStdin": true,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/tomcat/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"LANG=C.UTF-8",
"JAVA_HOME=/docker-java-home/jre",
"JAVA_VERSION=8u151",
"JAVA_DEBIAN_VERSION=8u151-b12-1~deb9u1",
"CA_CERTIFICATES_JAVA_VERSION=20170531+nmu1",
"CATALINA_HOME=/usr/local/tomcat",
"TOMCAT_NATIVE_LIBDIR=/usr/local/tomcat/native-jni-lib",
"LD_LIBRARY_PATH=/usr/local/tomcat/native-jni-lib",
"OPENSSL_VERSION=1.1.0f-3+deb9u1",
"GPG_KEYS=05AB33110949707C93A279E3D3EFE6B686867BA6 07E48665A34DCAFAE522E5E6266191C37C037D42 47309207D818FFD8DCD3F83F1931D684307A10A5 541FBE7D8F78B25E055DDEE13C370389288584E7 61B832AC2F1C5A90F0F9B00A1C506407564C17A3 713DA88BE50911535FE716F5208B0AB1D63011C7 79F7026C690BAA50B92CD8B66A3AD3F4F22C4FED 9BA44C2621385CB966EBA586F72C284D731FABEE A27677289986DB50844682F8ACB77FC2E86E29AC A9C5DF4D22E99998D9875A5110C01C5A2F6059E7 DCFD35E0BF8CA7344752DE8B6FB21E8933C60243 F3A04C595DB5B6A5F1ECA43E3B7BBB100D811BBE F7DA48BB64BCB84ECBA7EE6935CD23C10D498E23",
"TOMCAT_MAJOR=8",
"TOMCAT_VERSION=8.5.24",
"TOMCAT_SHA1=9e26ba61c5665aafc849073edeb769be555283cd",
"TOMCAT_TGZ_URLS=https://www.apache.org/dyn/closer.cgi?action=download&filename=tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz \thttps://www-us.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz \thttps://www.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz \thttps://archive.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz",
"TOMCAT_ASC_URLS=https://www.apache.org/dyn/closer.cgi?action=download&filename=tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc \thttps://www-us.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc \thttps://www.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc \thttps://archive.apache.org/dist/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz.asc"
],
"Cmd": [
"catalina.sh",
"run"
],
"ArgsEscaped": true,
"Image": "tomcat",
"Volumes": null,
"WorkingDir": "/usr/local/tomcat",
"Entrypoint": null,
"OnBuild": null,
"Labels": {}
},
"NetworkSettings": {
"Bridge": "",
"SandboxID": "50244517221e6faff4217ff5453919f0c297b10434812ecfbf3decb3ce9860f6",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {
"8080/tcp": null
},
"SandboxKey": "/var/run/docker/netns/50244517221e",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "e9336feece03b1c87e6724253575ee50963e9bdc1f9618609fe641a8a939b87a",
"Gateway": "172.17.0.1",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"IPAddress": "172.17.0.5",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"MacAddress": "02:42:ac:11:00:05",
"Networks": {
"bridge": {
"IPAMConfig": null,
"Links": null,
"Aliases": null,
"NetworkID": "87eb4d08d408c08489db4460915aabed59210d04f8193364420d3719cd308d83",
"EndpointID": "e9336feece03b1c87e6724253575ee50963e9bdc1f9618609fe641a8a939b87a",
"Gateway": "172.17.0.1",
"IPAddress": "172.17.0.5",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "02:42:ac:11:00:05"
}
}
}
}
]可见内容十分丰富；
如果我们只对其中的一些感兴趣，例如hostname、ip地址、环境变量，该如何查看呢？
1. hostname：在返回值中，hostname的位置如下图红框所示，
由上图可见，hostname位于Config.Hostname这个节点位置，所以执行命令docker inspect -f {{.Config.Hostname}} tomcat001即可获取到hostname，如下所示：
root@maven:~# docker inspect -f {{.Config.Hostname}} tomcat001
98d119ed4c73
2. ip地址：执行命令docker inspect -f {{.NetworkSettings.IPAddress}} tomcat001即可获取到ip地址：
root@maven:~# docker inspect -f {{.NetworkSettings.IPAddress}} tomcat001
172.17.0.5
3. 环境变量：从完整的inspect信息中可以看到环境变量Config.Env的内容是个json数组，所以除了用docker inspect -f {{.Config.Env}} tomcat001获取所有环境变量信息，还可以用docker inspect -f ‘{{index .Config.Env 1}}’ tomcat001命令获取数组中的某一条记录，如下：
root@maven:~# docker inspect -f '{{index .Config.Env 1}}' tomcat001
LANG=C.UTF-8
root@maven:~# docker inspect -f '{{index .Config.Env 2}}' tomcat001
JAVA_HOME=/docker-java-home/jre至此，三种获取容器信息的方式已经全部列出，之所以在本文中推荐第三种，是因为有时我们会在shell脚本中获取容器信息，这时候用这种方式最为简单；