Merge pull request #87 from Roblox/hostname

Add support for hostname.

Author: shishir-a412ed

README.md

@@ -100,6 +100,7 @@ More detailed instructions are in the [`example README.md`](https://github.com/R
 | **cwd** | string | no | Specify the current working directory for your container process. If the directory does not exist, one will be created for you. |
 | **privileged** | bool | no | Run container in privileged mode. Your container will have all linux capabilities when running in privileged mode. |
 | **pids_limit** | int64 | no | An integer value that specifies the pid limit for the container. Defaults to unlimited. |
+| **hostname** | string | no | The hostname to assign to the container. When launching more than one of a task (using `count`) with this option set, every container the task starts will have the same hostname. |
 | **host_dns** | bool | no | Default (`true`). By default, a container launched using `containerd-driver` will use host `/etc/resolv.conf`. This is similar to [`docker behavior`](https://docs.docker.com/config/containers/container-networking/#dns-services). However, if you don't want to use host DNS, you can turn off this flag by setting `host_dns=false`. |
 | **seccomp** | bool | no | Enable default seccomp profile. List of [`allowed syscalls`](https://github.com/containerd/containerd/blob/master/contrib/seccomp/seccomp_default.go#L51-L395). |
 | **seccomp_profile** | string | no | Path to custom seccomp profile. `seccomp` must be set to `true` in order to use `seccomp_profile`. The default `docker` seccomp profile found [`here`](https://github.com/moby/moby/blob/master/profiles/seccomp/default.json) can be used as a reference, and modified to create a custom seccomp profile. |

containerd/containerd.go

@@ -176,6 +176,13 @@ func (d *Driver) createContainer(containerConfig *ContainerConfig, config *TaskC
 	// Set CPU Shares.
 	opts = append(opts, oci.WithCPUShares(uint64(containerConfig.CPUShares)))
 
+	// Set Hostname
+	hostname := containerConfig.ContainerName
+	if config.Hostname != "" {
+		hostname = config.Hostname
+	}
+	opts = append(opts, oci.WithHostname(hostname))
+
 	// Add linux devices into the container.
 	for _, device := range config.Devices {
 		opts = append(opts, oci.WithLinuxDevice(device, "rwm"))

containerd/driver.go

@@ -100,6 +100,7 @@ var (
 		"devices":    hclspec.NewAttr("devices", "list(string)", false),
 		"privileged": hclspec.NewAttr("privileged", "bool", false),
 		"pids_limit": hclspec.NewAttr("pids_limit", "number", false),
+		"hostname":   hclspec.NewAttr("hostname", "string", false),
 		"host_dns": hclspec.NewDefault(
 			hclspec.NewAttr("host_dns", "bool", false),
 			hclspec.NewLiteral("true"),
@@ -169,6 +170,7 @@ type TaskConfig struct {
 	Sysctl           hclutils.MapStrStr `codec:"sysctl"`
 	Privileged       bool               `codec:"privileged"`
 	PidsLimit        int64              `codec:"pids_limit"`
+	Hostname         string             `codec:"hostname"`
 	HostDNS          bool               `codec:"host_dns"`
 	ImagePullTimeout string             `codec:"image_pull_timeout"`
 	ExtraHosts       []string           `codec:"extra_hosts"`

example/redis.nomad

@@ -6,9 +6,10 @@ job "redis" {
       driver = "containerd-driver"
 
       config {
-        image   = "redis:alpine"
-        seccomp = true
-        cwd     = "/home/redis"
+        image    = "redis:alpine"
+        hostname = "foobar"
+        seccomp  = true
+        cwd      = "/home/redis"
       }
 
       resources {

tests/001-test-redis.sh

@@ -34,6 +34,13 @@ test_redis_nomad_job() {
         exit 1
     fi
 
+    echo "INFO: Exec redis job and check hostname is foobar."
+    hostname=$(nomad alloc exec -job redis hostname)
+    if [ $hostname != "foobar" ]; then
+        echo "ERROR: hostname is not foobar."
+        exit 1
+    fi
+
     echo "INFO: Check if default seccomp is enabled."
     output=$(nomad alloc exec -job redis cat /proc/1/status | grep Seccomp)
     seccomp_code=$(echo $output|cut -d' ' -f2)