From bb4ad618e1bfb637fd700b9a2f222ce79f4c0814 Mon Sep 17 00:00:00 2001
From: Josh Curl <josh@curl.me>
Date: Thu, 3 Nov 2016 15:06:20 -0700
Subject: [PATCH] Implement bootcmd

---
 cmd/cloudinitexecute/cloudinitexecute.go        | 13 +------------
 cmd/control/bootstrap.go                        |  2 ++
 config/types.go                                 |  1 +
 docs/os/configuration/running-commands/index.md | 15 ++++++++++++++-
 init/bootstrap.go                               |  2 +-
 util/util.go                                    | 15 +++++++++++++++
 6 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/cmd/cloudinitexecute/cloudinitexecute.go b/cmd/cloudinitexecute/cloudinitexecute.go
index fd924d84..5a557028 100644
--- a/cmd/cloudinitexecute/cloudinitexecute.go
+++ b/cmd/cloudinitexecute/cloudinitexecute.go
@@ -94,18 +94,7 @@ func ApplyConsole(cfg *rancherConfig.CloudConfig) {
 		}
 	}
 
-	for _, runcmd := range cfg.Runcmd {
-		if len(runcmd) == 0 {
-			continue
-		}
-
-		cmd := exec.Command(runcmd[0], runcmd[1:]...)
-		cmd.Stdout = os.Stdout
-		cmd.Stderr = os.Stderr
-		if err := cmd.Run(); err != nil {
-			log.Errorf("Failed to run %s: %v", runcmd, err)
-		}
-	}
+	util.RunCommandSequence(cfg.Runcmd)
 }
 
 func WriteFiles(cfg *rancherConfig.CloudConfig, container string) {
diff --git a/cmd/control/bootstrap.go b/cmd/control/bootstrap.go
index 5051a506..b8b6cbb9 100644
--- a/cmd/control/bootstrap.go
+++ b/cmd/control/bootstrap.go
@@ -34,6 +34,8 @@ func bootstrapAction(c *cli.Context) error {
 		}
 	}
 
+	util.RunCommandSequence(cfg.Bootcmd)
+
 	if cfg.Rancher.State.Dev != "" && cfg.Rancher.State.Wait {
 		waitForRoot(cfg)
 	}
diff --git a/config/types.go b/config/types.go
index 33700668..2039daed 100644
--- a/config/types.go
+++ b/config/types.go
@@ -89,6 +89,7 @@ type CloudConfig struct {
 	Mounts            [][]string    `yaml:"mounts,omitempty"`
 	Rancher           RancherConfig `yaml:"rancher,omitempty"`
 	Runcmd            [][]string    `yaml:"runcmd,omitempty"`
+	Bootcmd           [][]string    `yaml:"bootcmd,omitempty"`
 }
 
 type File struct {
diff --git a/docs/os/configuration/running-commands/index.md b/docs/os/configuration/running-commands/index.md
index 3cb5f402..70177f61 100644
--- a/docs/os/configuration/running-commands/index.md
+++ b/docs/os/configuration/running-commands/index.md
@@ -21,7 +21,7 @@ Commands specified using `runcmd` will be executed within the context of the `co
 
 When using `runcmd`, RancherOS will wait for all commands to complete before starting Docker. As a result, any `docker run` command should not be placed under `runcmd`. Instead, the `/etc/rc.local` script can be used. RancherOS will not wait for commands in this script to complete, so you can use the `wait-for-docker` command to ensure that the Docker daemon is running before performing any `docker run` commands.
 
-```
+```yaml
 #cloud-config
 rancher:
 write_files:
@@ -35,3 +35,16 @@ write_files:
 ```
 
 Running Docker commands in this manner is useful when pieces of the `docker run` command are dynamically generated. For services whose configuration is static, [adding a system service]({{site.baseurl}}/os/system-services/adding-system-services/) is recommended.
+
+## Running Commands Early in the Boot Process
+---
+
+The `bootcmd` parameter can be used to run commands earlier in the boot process. In particular, `bootcmd` will be executed while RancherOS is still running from memory and before System Docker and any system services are started.
+
+The syntax for bootcmd is the same as `runcmd`.
+
+```yaml
+#cloud-config
+bootcmd:
+- [ mdadm, --assemble, --scan ]
+```
diff --git a/init/bootstrap.go b/init/bootstrap.go
index 026197bc..191da138 100644
--- a/init/bootstrap.go
+++ b/init/bootstrap.go
@@ -11,7 +11,7 @@ import (
 )
 
 func bootstrapServices(cfg *config.CloudConfig) (*config.CloudConfig, error) {
-	if len(cfg.Rancher.State.Autoformat) == 0 || util.ResolveDevice(cfg.Rancher.State.Dev) != "" {
+	if (len(cfg.Rancher.State.Autoformat) == 0 || util.ResolveDevice(cfg.Rancher.State.Dev) != "") && len(cfg.Bootcmd) == 0 {
 		return cfg, nil
 	}
 	log.Info("Running Bootstrap")
diff --git a/util/util.go b/util/util.go
index a58ef358..e89064f8 100644
--- a/util/util.go
+++ b/util/util.go
@@ -268,3 +268,18 @@ func RunScript(path string) error {
 
 	return cmd.Run()
 }
+
+func RunCommandSequence(commandSequence [][]string) {
+	for _, command := range commandSequence {
+		if len(command) == 0 {
+			continue
+		}
+
+		cmd := exec.Command(command[0], command[1:]...)
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		if err := cmd.Run(); err != nil {
+			log.Errorf("Failed to run %s: %v", command, err)
+		}
+	}
+}