examples: Add a minimal node_exporter example

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

examples/node_exporter.yml

@@ -0,0 +1,40 @@
+kernel:
+  image: "mobylinux/kernel:4.9.x"
+  cmdline: "console=ttyS0 page_poison=1"
+init:
+  - linuxkit/init:63eed9ca7a09d2ce4c0c5e7238ac005fa44f564b
+  - linuxkit/init:42fe8cb1508b3afed39eb89821906e3cc7a70551
+  - linuxkit/runc:b0fb122e10dbb7e4e45115177a61a3f8d68c19a9
+  - linuxkit/containerd:fe1b7f438a234cb6481c6538295115eac2a0596d
+services:
+  - name: rngd
+    image: "mobylinux/rngd:3dad6dd43270fa632ac031e99d1947f20b22eec9"
+    capabilities:
+     - CAP_SYS_ADMIN
+    oomScoreAdj: -800
+  - name: dhcpcd
+    image: "linuxkit/dhcpcd:48e249ebef6a521eed886b3bce032db69fbb4afa"
+    binds:
+     - /var:/var
+     - /tmp:/etc
+    capabilities:
+     - CAP_NET_ADMIN
+     - CAP_NET_BIND_SERVICE
+     - CAP_NET_RAW
+    net: host
+    oomScoreAdj: -800
+  - name: node_exporter
+    image: "linuxkit/node_exporter:0c7c1588e4cbce9cc946c1a84d3902b38b4b7ada"
+    capabilities:
+     - all
+    net: host
+    pid: host
+    binds:
+     - /proc:/host/proc
+     - /sys:/host/sys
+     - /:/rootfs
+trust:
+  image:
+    - mobylinux/kernel
+outputs:
+  - format: kernel+initrd