Re: Review Request 60600: Set container DNS with `--default_container_dns` in CNI isolator.

[Qian Zhang]

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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/60600/
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(Updated July 25, 2017, 2:06 p.m.)


Review request for mesos, Avinash sridharan and Jie Yu.


Changes
-------

Rebased.


Bugs: MESOS-7709
    https://issues.apache.org/jira/browse/MESOS-7709


Repository: mesos


Description
-------

Set container DNS with `--default_container_dns` in CNI isolator.


Diffs (updated)
-----

  src/slave/containerizer/mesos/isolators/network/cni/cni.cpp 
831bc7d0774a0ad3c8cbd7f42d4a3f8bd34d3243 


Diff: https://reviews.apache.org/r/60600/diff/4/

Changes: https://reviews.apache.org/r/60600/diff/3-4/


Testing
-------

sudo make check

1. Start Mesos master.
```
$ sudo ./bin/mesos-master.sh --work_dir=/opt/mesos
```

2. Start Mesos agent.
```
$ sudo ./bin/mesos-slave.sh --master=192.168.122.216:5050 
--containerizers=mesos,docker --image_providers=docker 
--image_provisioner_backend=aufs 
--isolation=filesystem/linux,docker/runtime,network/cni,cgroups/cpu,cgroups/mem 
--network_cni_config_dir=/opt/cni/net_configs 
--network_cni_plugins_dir=/opt/cni/plugins --work_dir=/opt/mesos 
--docker_store_dir=/opt/mesos/store/docker 
--executor_registration_timeout=60mins 
--default_container_dns=file:///home/stack/dns.json

$ cat /opt/cni/net_configs/net1 
{
    "name": "net1",
    "type": "bridge",
    "bridge": "br1",
    "isGateway": true,
    "ipMasq": true,
    "ipam": {
        "type": "host-local",
        "subnet": "192.168.1.0/24",
        "routes": [
            { "dst": "0.0.0.0/0" }
        ]
    }
}

$ cat /opt/cni/net_configs/net2 
{
    "name": "net2",
    "type": "bridge",
    "bridge": "br2",
    "isGateway": true,
    "ipMasq": true,
    "ipam": {
        "type": "host-local",
        "subnet": "192.168.2.0/24",
        "routes": [
            { "dst": "0.0.0.0/0" }
        ]
    },
    "dns": {
        "nameservers": [ "8.8.4.4" ],
        "domain": "net2.com",
        "search": [ "yyy.com" ],
        "options": [ "attempts:3" ]
    }
}

$ cat /home/stack/dns.json
{
  "mesos": [
    {
      "network_mode": "CNI",
      "network_name": "net1",
      "dns": {
        "nameservers": [ "8.8.8.8" ],
        "search": [ "xxx.com" ],
        "options": [ "timeout:4" ]
      }
    }
  ]
}
```

3. Launch a unified container with `mesos-execute`.
```
$ sudo src/mesos-execute --master=192.168.122.216:5050 
--task=file:///home/stack/task.json

$ cat /home/stack/task.json 
{
  "name": "test",
  "task_id": {"value" : "test"},
  "agent_id": {"value" : ""},
  "resources": [
    {
      "name": "cpus",
      "type": "SCALAR",
      "scalar": {
        "value": 0.1
      }
    },
    {
      "name": "mem",
      "type": "SCALAR",
      "scalar": {
        "value": 32
      }
    }
  ],
  "command": {
    "value": "sleep 300"
  },
  "container": {
    "type": "MESOS",
    "mesos": {
      "image": {
        "type": "DOCKER",
        "docker": {
          "name": "busybox"
        }
      }
    },
    "network_infos": [
      {
        "name": "net1"
      },
      {
        "name": "net2"
      }
    ]
  }
}
```

4. Check the DNS configuration of the unified container.
```
$ ps -ef | grep sleep 
root     20060 20037  2 21:45 ?        00:00:00 sh -c sleep 300
root     20074 20060  0 21:45 ?        00:00:00 sleep 300

$ sudo nsenter -t 20060 -m -u -n cat /etc/resolv.conf           
domain net2.com
search yyy.com xxx.com
options attempts:3 timeout:4
nameserver 8.8.4.4
nameserver 8.8.8.8
```


Thanks,

Qian Zhang