lxd: Add tests

Author: Patryk27

nixos/tests/all-tests.nix

@@ -178,6 +178,8 @@ in
   limesurvey = handleTest ./limesurvey.nix {};
   login = handleTest ./login.nix {};
   loki = handleTest ./loki.nix {};
+  lxd = handleTest ./lxd.nix {};
+  lxd-nftables = handleTest ./lxd-nftables.nix {};
   #logstash = handleTest ./logstash.nix {};
   lorri = handleTest ./lorri/default.nix {};
   magnetico = handleTest ./magnetico.nix {};

nixos/tests/lxd-nftables.nix

@@ -0,0 +1,50 @@
+# This test makes sure that lxd stops implicitly depending on iptables when
+# user enabled nftables.
+#
+# It has been extracted from `lxd.nix` for clarity, and because switching from
+# iptables to nftables requires a full reboot, which is a bit hard inside NixOS
+# tests.
+
+import ./make-test-python.nix ({ pkgs, ...} : {
+  name = "lxd-nftables";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ patryk27 ];
+  };
+
+  machine = { lib, ... }: {
+    virtualisation = {
+      lxd.enable = true;
+    };
+
+    networking = {
+      firewall.enable = false;
+      nftables.enable = true;
+      nftables.ruleset = ''
+        table inet filter {
+          chain incoming {
+            type filter hook input priority 0;
+            policy accept;
+          }
+
+          chain forward {
+            type filter hook forward priority 0;
+            policy accept;
+          }
+
+          chain output {
+            type filter hook output priority 0;
+            policy accept;
+          }
+        }
+      '';
+    };
+  };
+
+  testScript = ''
+    machine.wait_for_unit("network.target")
+
+    with subtest("When nftables are enabled, lxd doesn't depend on iptables anymore"):
+        machine.succeed("lsmod | grep nf_tables")
+        machine.fail("lsmod | grep ip_tables")
+  '';
+})

nixos/tests/lxd.nix

@@ -0,0 +1,135 @@
+import ./make-test-python.nix ({ pkgs, ...} :
+
+let
+  # Since we don't have access to the internet during the tests, we have to
+  # pre-fetch lxd containers beforehand.
+  #
+  # I've chosen to import Alpine Linux, because its image is turbo-tiny and,
+  # generally, sufficient for our tests.
+
+  alpine-meta = pkgs.fetchurl {
+    url = "https://uk.images.linuxcontainers.org/images/alpine/3.11/i386/default/20200608_13:00/lxd.tar.xz";
+    sha256 = "1hkvaj3rr333zmx1759njy435lps33gl4ks8zfm7m4nqvipm26a0";
+  };
+
+  alpine-rootfs = pkgs.fetchurl {
+    url = "https://uk.images.linuxcontainers.org/images/alpine/3.11/i386/default/20200608_13:00/rootfs.tar.xz";
+    sha256 = "1v82zdra4j5xwsff09qlp7h5vbsg54s0j7rdg4rynichfid3r347";
+  };
+
+  lxd-config = pkgs.writeText "config.yaml" ''
+    storage_pools:
+      - name: default
+        driver: dir
+        config:
+          source: /var/lxd-pool
+
+    networks:
+      - name: lxdbr0
+        type: bridge
+        config:
+          ipv4.address: auto
+          ipv6.address: none
+
+    profiles:
+      - name: default
+        devices:
+          eth0:
+            name: eth0
+            network: lxdbr0
+            type: nic
+          root:
+            path: /
+            pool: default
+            type: disk
+  '';
+
+in {
+  name = "lxd";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ patryk27 ];
+  };
+
+  machine = { lib, ... }: {
+    virtualisation = {
+      # Since we're testing `limits.cpu`, we've gotta have a known number of
+      # cores to lay on
+      cores = 2;
+
+      # Ditto, for `limits.memory`
+      memorySize = 512;
+
+      lxc.lxcfs.enable = true;
+      lxd.enable = true;
+    };
+  };
+
+  testScript = ''
+    machine.wait_for_unit("sockets.target")
+    machine.wait_for_unit("lxd.service")
+
+    # It takes additional second for lxd to settle
+    machine.sleep(1)
+
+    # lxd expects the pool's directory to already exist
+    machine.succeed("mkdir /var/lxd-pool")
+
+    machine.succeed(
+        "cat ${lxd-config} | lxd init --preseed"
+    )
+
+    machine.succeed(
+        "lxc image import ${alpine-meta} ${alpine-rootfs} --alias alpine"
+    )
+
+    with subtest("Containers can be launched and destroyed"):
+        machine.succeed("lxc launch alpine test")
+        machine.succeed("lxc exec test true")
+        machine.succeed("lxc delete -f test")
+
+    with subtest("Containers are being mounted with lxcfs inside"):
+        machine.succeed("lxc launch alpine test")
+
+        ## ---------- ##
+        ## limits.cpu ##
+
+        machine.succeed("lxc config set test limits.cpu 1")
+
+        # Since Alpine doesn't have `nproc` pre-installed, we've gotta resort
+        # to the primal methods
+        assert (
+            "1"
+            == machine.succeed("lxc exec test grep -- -c ^processor /proc/cpuinfo").strip()
+        )
+
+        machine.succeed("lxc config set test limits.cpu 2")
+
+        assert (
+            "2"
+            == machine.succeed("lxc exec test grep -- -c ^processor /proc/cpuinfo").strip()
+        )
+
+        ## ------------- ##
+        ## limits.memory ##
+
+        machine.succeed("lxc config set test limits.memory 64MB")
+
+        assert (
+            "MemTotal:          62500 kB"
+            == machine.succeed("lxc exec test grep -- MemTotal /proc/meminfo").strip()
+        )
+
+        machine.succeed("lxc config set test limits.memory 128MB")
+
+        assert (
+            "MemTotal:         125000 kB"
+            == machine.succeed("lxc exec test grep -- MemTotal /proc/meminfo").strip()
+        )
+
+        machine.succeed("lxc delete -f test")
+
+    with subtest("Unless explicitly changed, lxd leans on iptables"):
+        machine.succeed("lsmod | grep ip_tables")
+        machine.fail("lsmod | grep nf_tables")
+  '';
+})