Docker container has no IP address. What for?
I started a docker container rethinkDB
using the command
docker pull rethinkdb:2.3
docker run --rm --name rethinkdb -v /srv/rethinkdb:/data --net host rethinkdb:2.3 rethinkdb --bind all --cache-size 8192 --no-update-check
The container has now started successfully. I diddocker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f288961ef376 rethinkdb:2.3 "rethinkdb --bind ..." 9 minutes ago Up 9 minutes rethinkdb
1f71722698ae sorccu/adb:latest "/sbin/tini -- adb..." 14 minutes ago Up 14 minutes adbd
Now I want to find out the IP address of this container. So I did
docker inspect --format '{{ .NetworkSettings.IPAddress }}' f288961ef376
It doesn't return anything to me. I couldn't find the IP address for this container.
I checked if the config page is rethinkDB
inserted or not by going to http://localhost:8080
and I can see it working.
Why doesn't this container have an IP address?
The output docker inspect
looks like this
[
{
"Id": "f288961ef376531c97d2264cb8ef3c6077a6a75107905d6a47734303adfcb117",
"Created": "2017-05-05T11:13:45.382460184Z",
"Path": "rethinkdb",
"Args": [
"--bind",
"all",
"--cache-size",
"8192",
"--no-update-check"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 8157,
"ExitCode": 0,
"Error": "",
"StartedAt": "2017-05-05T11:13:45.774035358Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "sha256:c5ed876750b40cde4725ea9eb9d8503f4d1419a2f23ac2ef8e4cc1d535e2c3a2",
"ResolvConfPath": "/var/lib/docker/containers/f288961ef376531c97d2264cb8ef3c6077a6a75107905d6a47734303adfcb117/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/f288961ef376531c97d2264cb8ef3c6077a6a75107905d6a47734303adfcb117/hostname",
"HostsPath": "/var/lib/docker/containers/f288961ef376531c97d2264cb8ef3c6077a6a75107905d6a47734303adfcb117/hosts",
"LogPath": "/var/lib/docker/containers/f288961ef376531c97d2264cb8ef3c6077a6a75107905d6a47734303adfcb117/f288961ef376531c97d2264cb8ef3c6077a6a75107905d6a47734303adfcb117-json.log",
"Name": "/rethinkdb",
"RestartCount": 0,
"Driver": "aufs",
"MountLabel": "",
"ProcessLabel": "",
"AppArmorProfile": "docker-default",
"ExecIDs": null,
"HostConfig": {
"Binds": [
"/srv/rethinkdb:/data"
],
"ContainerIDFile": "",
"LogConfig": {
"Type": "json-file",
"Config": {}
},
"NetworkMode": "host",
"PortBindings": {},
"RestartPolicy": {
"Name": "no",
"MaximumRetryCount": 0
},
"AutoRemove": true,
"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": [],
"DeviceCgroupRules": null,
"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": {
"Data": null,
"Name": "aufs"
},
"Mounts": [
{
"Type": "bind",
"Source": "/srv/rethinkdb",
"Destination": "/data",
"Mode": "",
"RW": true,
"Propagation": ""
}
],
"Config": {
"Hostname": "dev-machine",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": true,
"AttachStderr": true,
"ExposedPorts": {
"28015/tcp": {},
"29015/tcp": {},
"8080/tcp": {}
},
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"RETHINKDB_PACKAGE_VERSION=2.3.5~0jessie"
],
"Cmd": [
"rethinkdb",
"--bind",
"all",
"--cache-size",
"8192",
"--no-update-check"
],
"Image": "rethinkdb:2.3",
"Volumes": {
"/data": {}
},
"WorkingDir": "/data",
"Entrypoint": null,
"OnBuild": null,
"Labels": {}
},
"NetworkSettings": {
"Bridge": "",
"SandboxID": "bd17bf8e1663ff18f6674a1a3a1665c4e1bf65283d358ffc97dc238ef4a79088",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {},
"SandboxKey": "/var/run/docker/netns/default",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "",
"Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"IPAddress": "",
"IPPrefixLen": 0,
"IPv6Gateway": "",
"MacAddress": "",
"Networks": {
"host": {
"IPAMConfig": null,
"Links": null,
"Aliases": null,
"NetworkID": "30b6150968580d33aae0e45f7d850b9e67ae2aa29e1bb837ca4fa74f2b0d4d42",
"EndpointID": "05e93ec514ee6694e57d344f3e4362252104347c3cc48c607708d125715ed6ec",
"Gateway": "",
"IPAddress": "",
"IPPrefixLen": 0,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": ""
}
}
}
}
]
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You start your container with an option --net host
, which means your container will run on your host network. Read more about here . This way, your container will be available on your host's IP.
The simplest example:
$ docker run --net=host -d jenkins
This will launch jenkins on your real host network. So when you open the firewall (jenkins starts at 8080) you will have access to your container immediately. So I open up the firewall:
$ sudo iptables -I INPUT 5 -p tcp -m tcp --dport 8080 -j ACCEPT
I am checking the real IP address of my eth0 (host network) with ifconfig
. (I am doing this in a virtual machine). This is inet 192.168.140.7
. I go to my browser to 192.168.140.7:8080 and I see the jenkins. Thus, your container does not have its own IP address. It works on your host network and host IP.
If you leave the parameter --net host
, the container will be created on the default docker bridge network with a range "172.17.0.0/16"
. Your container will now receive an IP address within this network. To access the container from the outside, you need to map your ports on the host's network (see more information). You can do this with an option -p
.
So for the jenkins example:
$ docker run -d -p 8888:8080 jenkins
When I execute a docker inspect
, I see:
"IPAddress": "172.17.0.4",
So my container is running on the bridge network at 172.17.0.4:8080. Now with the option, -p
I map port 8080 of my bridged network to 8888 of my host network: so host-IP:8888
. It is now accessible from the outside.
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Your container ip is the same as the host. host
basically says your container is using the same network interface as the host. It's fast because there are no bridges, but limited; You need to make sure your containers are not listening on the same port to avoid conflicts.
Better to stick with the default network bridge
and specify the port you want to open for the host. For example:
docker run --rm --name rethinkdb -v /srv/rethinkdb:/data -p 8080:8080 \
rethinkdb:2.3 rethinkdb --bind all --cache-size 8192 --no-update-check
btw --net
was renamed to --network
in later versions of Docker.
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