daemon: updated docker nodes to start using tail to keep alive, adjustments to support more robust volume mounting and adding symlinks to the nodes directory for bind/volume mounts

daemon/core/emulator/data.py

@@ -2,7 +2,7 @@
 CORE data objects.
 """
 from dataclasses import dataclass, field
-from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, List, Optional, Tuple
 
 import netaddr
 
@@ -92,8 +92,10 @@ class NodeOptions:
     image: str = None
     emane: str = None
     legacy: bool = False
-    binds: Dict[str, str] = field(default_factory=dict)
-    volumes: Dict[str, str] = field(default_factory=dict)
+    # src, dst
+    binds: List[Tuple[str, str]] = field(default_factory=list)
+    # src, dst, unique, delete
+    volumes: List[Tuple[str, str, bool, bool]] = field(default_factory=list)
 
     def set_position(self, x: float, y: float) -> None:
         """

daemon/core/nodes/docker.py

@@ -4,7 +4,7 @@ import shlex
 from dataclasses import dataclass
 from pathlib import Path
 from tempfile import NamedTemporaryFile
-from typing import TYPE_CHECKING, Dict
+from typing import TYPE_CHECKING, Dict, List, Tuple
 
 from core.emulator.distributed import DistributedServer
 from core.errors import CoreCommandError, CoreError
@@ -23,6 +23,8 @@ DOCKER: str = "docker"
 class DockerVolume:
     src: str
     dst: str
+    unique: bool = True
+    delete: bool = True
     path: str = None
 
 
@@ -39,8 +41,8 @@ class DockerNode(CoreNode):
         directory: str = None,
         server: DistributedServer = None,
         image: str = None,
-        binds: Dict[str, str] = None,
-        volumes: Dict[str, str] = None,
+        binds: List[Tuple[str, str]] = None,
+        volumes: List[Tuple[str, str, bool, bool]] = None,
     ) -> None:
         """
         Create a DockerNode instance.
@@ -53,15 +55,16 @@ class DockerNode(CoreNode):
             will run on, default is None for localhost
         :param image: image to start container with
         :param binds: bind mounts to set for the created container
-        :param volumes: volume mounts to set for the created container
+        :param volumes: volume mount settings to set for the created container
         """
         super().__init__(session, _id, name, directory, server)
         self.image: str = image if image is not None else "ubuntu"
-        self.binds: Dict[str, str] = binds or {}
-        volumes = volumes or {}
-        self.volumes: Dict[str, DockerVolume] = {
-            k: DockerVolume(k, v) for k, v in volumes.items()
-        }
+        self.binds: List[Tuple[str, str]] = binds or []
+        self.volumes: Dict[str, DockerVolume] = {}
+        volumes = volumes or []
+        for src, dst, unique, delete in volumes:
+            src_name = self._unique_name(src) if unique else src
+            self.volumes[src] = DockerVolume(src_name, dst, unique, delete)
 
     def _create_cmd(self, args: str, shell: bool = False) -> str:
         """
@@ -75,6 +78,15 @@ class DockerNode(CoreNode):
             args = f"{BASH} -c {shlex.quote(args)}"
         return f"nsenter -t {self.pid} -m -u -i -p -n {args}"
 
+    def _unique_name(self, name: str) -> str:
+        """
+        Creates a session/node unique prefixed name for the provided input.
+
+        :param name: name to make unique
+        :return: unique session/node prefixed name
+        """
+        return f"{self.session.id}.{self.id}.{name}"
+
     def alive(self) -> bool:
         """
         Check if the node is alive.
@@ -100,7 +112,7 @@ class DockerNode(CoreNode):
                 raise CoreError(f"starting node({self.name}) that is already up")
             self.makenodedir()
             binds = ""
-            for src, dst in self.binds.items():
+            for src, dst in self.binds:
                 binds += f"--mount type=bind,source={src},target={dst} "
             volumes = ""
             for volume in self.volumes.values():
@@ -111,15 +123,20 @@ class DockerNode(CoreNode):
                 f"{DOCKER} run -td --init --net=none --hostname {self.name} "
                 f"--name {self.name} --sysctl net.ipv6.conf.all.disable_ipv6=0 "
                 f"{binds} {volumes} "
-                f"--privileged {self.image} /bin/bash"
+                f"--privileged {self.image} tail -f /dev/null"
             )
             self.pid = self.host_cmd(
                 f"{DOCKER} inspect -f '{{{{.State.Pid}}}}' {self.name}"
             )
+            for src, dst in self.binds:
+                link_path = self.host_path(Path(dst), True)
+                self.host_cmd(f"ln -s {src} {link_path}")
             for volume in self.volumes.values():
                 volume.path = self.host_cmd(
                     f"{DOCKER} volume inspect -f '{{{{.Mountpoint}}}}' {volume.src}"
                 )
+                link_path = self.host_path(Path(volume.dst), True)
+                self.host_cmd(f"ln -s {volume.path} {link_path}")
             logger.debug("node(%s) pid: %s", self.name, self.pid)
             self.up = True
 
@@ -136,6 +153,7 @@ class DockerNode(CoreNode):
             self.ifaces.clear()
             self.host_cmd(f"{DOCKER} rm -f {self.name}")
             for volume in self.volumes.values():
+                if volume.delete:
                     self.host_cmd(f"{DOCKER} volume rm {volume.src}")
             self.up = False