Feature 57 (config and provisioning): modules declare config and provisions, their files rendered from templates; synced with main (issues of feature 57, 874)

modules/kernel/module.json

@@ -0,0 +1,77 @@
+{
+  "module": "kernel",
+  "version": "1",
+  "capabilities": [
+    "service-manager"
+  ],
+  "config": {
+    "transparent-huge-pages": {
+      "type": "string",
+      "description": "madvise is the value the mesh chose for every node (novox/hq ADR 0381), not the always the distribution's kernel boots with; a machine that needs another value is given it as its own setting; madvise gives huge pages only to programs that ask for them, which stops a small write to a mapped file (the journal) dirtying and writing back a whole 2 MiB page on a machine whose disks are slow (novox/hq issue 746)",
+      "trusted": true,
+      "default": "madvise"
+    }
+  },
+  "tools": [
+    "kernel_huge_pages"
+  ],
+  "resources": [
+    {
+      "id": "state",
+      "type": "directory",
+      "mode": "0700",
+      "place": "."
+    },
+    {
+      "id": "huge-pages",
+      "type": "file",
+      "path": "${dir:state}/huge-pages",
+      "mode": "0755",
+      "trusted": true,
+      "template": "files/huge-pages.sh"
+    },
+    {
+      "id": "unit",
+      "type": "file",
+      "path": "/etc/systemd/system/mesh-kernel-huge-pages.service",
+      "mode": "0644",
+      "template": "files/mesh-kernel-huge-pages.service"
+    },
+    {
+      "id": "apply",
+      "type": "service",
+      "unit": "mesh-kernel-huge-pages.service",
+      "state": "running",
+      "boot": "enabled",
+      "restart-on": [
+        "unit"
+      ],
+      "reload-on": [
+        "huge-pages"
+      ],
+      "health": {
+        "kind": "unit"
+      }
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "tools",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/kernel-tools",
+        "binary": "kernel-tools",
+        "loads": [
+          "kernel-tools"
+        ]
+      },
+      {
+        "name": "files",
+        "kind": "archive",
+        "from": "files"
+      }
+    ]
+  }
+}