Support dhcpcd in one shot mode as well

This is needed for cloud environments that want to get their metadata in
the onboot phase over the network.

Signed-off-by: Justin Cormack <justin.cormack@docker.com>

examples/gcp.yml

@@ -15,6 +15,17 @@ onboot:
     capabilities:
      - CAP_SYS_ADMIN
     readonly: true
+  - name: dhcpcd
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
+    binds:
+     - /var:/var
+     - /tmp:/etc
+    capabilities:
+     - CAP_NET_ADMIN
+     - CAP_NET_BIND_SERVICE
+     - CAP_NET_RAW
+    net: host
+    command: ["/sbin/dhcpcd", "--nobackground", "-f", "/dhcpcd.conf", "-1"]
   - name: metadata-gcp
     image: "mobylinux/metadata-gcp:7fc3dd5ef92e0408fb3f76048bbaae88bbb55ad9"
     binds:
@@ -32,17 +43,6 @@ services:
      - CAP_SYS_ADMIN
     oomScoreAdj: -800
     readonly: true
-  - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
-    binds:
-     - /var:/var
-     - /tmp:/etc
-    capabilities:
-     - CAP_NET_ADMIN
-     - CAP_NET_BIND_SERVICE
-     - CAP_NET_RAW
-    net: host
-    oomScoreAdj: -800
   - name: sshd
     image: "mobylinux/sshd:160631d59fffc13d523ff7f09b3b49538d34b9cd"
     capabilities:

examples/sshd.yml

@@ -21,7 +21,7 @@ services:
      - CAP_SYS_ADMIN
     oomScoreAdj: -800
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp:/etc

examples/vmware.yml

@@ -23,7 +23,7 @@ services:
     oomScoreAdj: -800
     readonly: true
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp:/etc

moby.yml

@@ -20,15 +20,8 @@ onboot:
     binds:
      - /proc/sys/fs/binfmt_misc:/binfmt_misc
     readonly: true
-services:
-  - name: rngd
-    image: "mobylinux/rngd:3dad6dd43270fa632ac031e99d1947f20b22eec9@sha256:1c93c1db7196f6f71f8e300bc1d15f0376dd18e8891c8789d77c8ff19f3a9a92"
-    capabilities:
-     - CAP_SYS_ADMIN
-    oomScoreAdj: -800
-    readonly: true
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp/etc:/etc
@@ -37,7 +30,14 @@ services:
      - CAP_NET_BIND_SERVICE
      - CAP_NET_RAW
     net: host
+    command: ["/sbin/dhcpcd", "--nobackground", "-f", "/dhcpcd.conf", "-1"]
+services:
+  - name: rngd
+    image: "mobylinux/rngd:3dad6dd43270fa632ac031e99d1947f20b22eec9@sha256:1c93c1db7196f6f71f8e300bc1d15f0376dd18e8891c8789d77c8ff19f3a9a92"
+    capabilities:
+     - CAP_SYS_ADMIN
     oomScoreAdj: -800
+    readonly: true
   - name: nginx
     image: "nginx:alpine"
     capabilities:

pkg/dhcpcd/dhcpcd.conf

@@ -41,3 +41,6 @@ nodelay
 
 # Do not arp to check IP
 noarp
+
+# wait for ipv4 address
+waitip 4

projects/demo/etcd/etcd.yml

@@ -39,7 +39,7 @@ services:
     oomScoreAdj: -800
     readonly: true
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp/etc:/etc

projects/demo/intro/intro.yml

@@ -16,7 +16,7 @@ onboot:
     readonly: true
 services:
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp/etc:/etc

projects/swarmd/swarmd.yml

@@ -20,7 +20,7 @@ services:
     oomScoreAdj: -800
     readonly: true
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp/etc:/etc

test/docker-bench/test-docker-bench.yml

@@ -81,4 +81,4 @@ trust:
   image:
     - mobylinux/kernel
 outputs:
-  - format: kernel+initrd
+  - format: kernel+initrd

test/ltp/test-ltp.yml

@@ -15,7 +15,7 @@ onboot:
      - CAP_SYS_ADMIN
 services:
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp:/etc

test/test.yml

@@ -7,15 +7,8 @@ init:
   - mobylinux/containerd:18eaf72f3f4f9a9f29ca1951f66df701f873060b
   - mobylinux/ca-certificates:eabc5a6e59f05aa91529d80e9a595b85b046f935
 onboot:
-  - name: check
-    image: "mobylinux/check:c9e41ab96b3ea6a3ced97634751e20d12a5bf52f"
-    pid: host
-    capabilities:
-     - CAP_SYS_BOOT
-    readonly: true
-services:
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp:/etc
@@ -24,7 +17,13 @@ services:
      - CAP_NET_BIND_SERVICE
      - CAP_NET_RAW
     net: host
-    oomScoreAdj: -800
+    command: ["/sbin/dhcpcd", "--nobackground", "-f", "/dhcpcd.conf", "-1"]
+  - name: check
+    image: "mobylinux/check:c9e41ab96b3ea6a3ced97634751e20d12a5bf52f"
+    pid: host
+    capabilities:
+     - CAP_SYS_BOOT
+    readonly: true
 outputs:
   - format: kernel+initrd
   - format: iso-bios

test/virtsock/test-virtsock-server.yml

@@ -27,7 +27,7 @@ services:
     oomScoreAdj: -800
     readonly: true
   - name: dhcpcd
-    image: "mobylinux/dhcpcd:3eb32da7ff8051f61e0f18edd90dd0fbfcf148ea"
+    image: "mobylinux/dhcpcd:0d4012269cb142972fed8542fbdc3ff5a7b695cd"
     binds:
      - /var:/var
      - /tmp:/etc