add useful testing script to quickly update stemcells with local agen…

…t binary

Signed-off-by: Brian Cunnie <[email protected]>

bin/repack-stemcell/README.md

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+# Repacking Stemcell with Updated Agent
+
+!!! For debugging only !!!
+
+This Concourse task allows the customization of a stemcell's `bosh-agent`, typically used when testing bootstrapping stage. Consider scp-ing Agent binary onto running machine as a quicker alternative.
+
+Override STEMCELL_URL (must be heavy stemcell, raw) and STEMCELL_SHA1 to the stemcell you want (or leave as is):
+
+```
+export STEMCELL_URL=https://s3.amazonaws.com/bosh-core-stemcells/aws/bosh-stemcell-3312.15-aws-xen-ubuntu-trusty-go_agent.tgz
+export STEMCELL_SHA1=d5252cdd6b07763ed989fcfeff47d06afa164065
+./run.sh
+```
+
+Assumes your Concourse target is named _production_. If not, edit `run.sh` and adjust.
+
+### Optional SSH debugging
+
+Set your SSH key:
+
+```
+export BOSH_DEBUG_PUB_KEY="ssh-rsa blahblah"
+```
+
+This will bake your SSH public key into the stemcell; you will be able to ssh in as user `bosh_debug`.

bin/repack-stemcell/repack.sh

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+#!/bin/bash
+
+set -e -x
+
+env
+
+stemcell_tgz=/tmp/stemcell.tgz
+stemcell_dir=/tmp/stemcell
+image_dir=/tmp/image
+
+mkdir -p $stemcell_dir $image_dir
+wget -O- $STEMCELL_URL > $stemcell_tgz
+echo "$STEMCELL_SHA1  $stemcell_tgz" | shasum -c -
+
+# Expose loopbacks in concourse container
+(
+  set -e
+  mount_path=/tmp/self-cgroups
+  cgroups_path=`cat /proc/self/cgroup|grep devices|cut -d: -f3`
+  [ -d $mount_path ] && umount $mount_path && rmdir $mount_path
+  mkdir -p $mount_path
+  mount -t cgroup -o devices none $mount_path
+  echo 'b 7:* rwm' > $mount_path/$cgroups_path/devices.allow
+  umount $mount_path
+  rmdir $mount_path
+  for i in $(seq 0 260); do
+  	mknod -m660 /dev/loop${i} b 7 $i 2>/dev/null || true
+  done
+)
+
+# Repack stemcell
+(
+	set -e;
+	cd $stemcell_dir
+	tar xvf $stemcell_tgz
+	new_ver=`date +%s`
+
+	# Update stemcell with new agent
+	(
+		set -e;
+		cd $image_dir
+		tar xvf $stemcell_dir/image
+		mnt_dir=/mnt/stemcell
+		mkdir $mnt_dir
+		mount -o loop,offset=32256 root.img $mnt_dir
+		echo -n 0.0.${new_ver} > $mnt_dir/var/vcap/bosh/etc/stemcell_version
+		cp /tmp/build/*/agent-src/bin/bosh-agent $mnt_dir/var/vcap/bosh/bin/bosh-agent
+
+		if [ -z "$BOSH_DEBUG_PUB_KEY" ]; then
+			sudo chroot $mnt_dir /bin/bash <<EOF
+				useradd -m -s /bin/bash bosh_debug -G bosh_sudoers
+				cd ~bosh_debug
+				mkdir .ssh
+				echo $BOSH_DEBUG_PUB_KEY >> .ssh/authorized_keys
+				chmod go-rw -R .
+				chown -R bosh_debug:bosh_debug .
+EOF
+    fi
+
+		umount $mnt_dir
+		tar czvf $stemcell_dir/image *
+	)
+
+	sed -i.bak "s/version: .*/version: 0.0.${new_ver}/" stemcell.MF
+	tar czvf $stemcell_tgz *
+)
+
+cp $stemcell_tgz /tmp/build/*/stemcell/

bin/repack-stemcell/run.sh

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+#!/bin/bash
+
+set -e -x
+
+bin=$(dirname $0)
+cd $bin/../..
+./bin/build-linux-amd64
+mv out/bosh-agent bin/bosh-agent # necessary so that fly -x can be used
+time fly -t production execute -x -p -i agent-src=. -o stemcell=out/ -c ./bin/build-stemcell/task.yml
+ls -la out/stemcell.tgz

bin/repack-stemcell/task.yml

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+---
+platform: linux
+
+image_resource:
+  type: docker-image
+  source:
+    repository: bosh/os-image-stemcell-builder
+
+inputs:
+  - name: agent-src
+
+outputs:
+  - name: stemcell
+
+run:
+  path: agent-src/bin/build-stemcell/repack.sh
+
+params:
+  STEMCELL_URL: "https://s3.amazonaws.com/bosh-core-stemcells/aws/bosh-stemcell-3312.15-aws-xen-ubuntu-trusty-go_agent.tgz"
+  STEMCELL_SHA1: "d5252cdd6b07763ed989fcfeff47d06afa164065"
+  BOSH_DEBUG_PUB_KEY: ""