Merge ~raharper/curtin:fix/centos-grub into curtin:master

[Ryan Harper]

vmtest/centos: handle different paths to grub config

Centos images used to always have grub installed at
/boot/grub/grub.conf. The most recent build of centos70,
centos70/amd64/20210210_01/root-tgz, now has grub conf located at
/boot/grub2/grub.cfg. This patch checks for either path before
running the sed fixup command.

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:a011d9d8e965fd87e737a380e6fa3423b6ee3634
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    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-ppc64el/98/
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review: Approve (continuous-integration)

[Michael Hudson-Doyle (mwhudson)]

As discussed on IRC this is possibly more than is needed. Indeed it seems that MAAS no longer publishes centos 6 images at all so maybe all of this can be droppped. But it fixes the tests so I'm going to merge this and then we can work on cleaning it up later.

diff --git a/examples/tests/centos_defaults.yaml b/examples/tests/centos_defaults.yaml
index 85e1c03..94e2ae8 100644
--- a/examples/tests/centos_defaults.yaml
+++ b/examples/tests/centos_defaults.yaml
@@ -27,7 +27,7 @@ write_files:
           [ -e "$ofile" ] || return 0
           cp "$ofile" "$bk" || rerror "failed backup ($ofile -> $bk):" "$@";
       }
-      
+
       update_grub1() {
           local cfg="$1" r=""
           [ -e "$cfg" ] ||
@@ -48,7 +48,7 @@ write_files:
               { rerror "failed to update grub1 cfg '$cfg'."; return; }
           info "updated grub1 cfg '$cfg'."
       }
-      
+
       update_grub2() {
           local cfg="$1" defgrub="$2"
           [ -e "$cfg" ] || { info "no grub2 config '$cfg'"; return 0; }
@@ -56,8 +56,8 @@ write_files:
           sed -i -e '/kernel/n' -e '/console=/n' \
             -e "s/root=\([^ ]*\)/root=\1 ${CONPARM}/" "$cfg" ||
             { rerror "failed to update grub2 '$cfg'"; return; }
-      
-          # update /etc/default/grub. any GRUB_CMDLINE_LINUX remove 
+
+          # update /etc/default/grub. any GRUB_CMDLINE_LINUX remove
           # any console= and add conparm at the beginning.
           local var="GRUB_CMDLINE_LINUX" msg="updated grub2 '$cfg'."
           if [ ! -e "$defgrub" ]; then
@@ -77,15 +77,21 @@ write_files:
       update_grub1 "$grub1conf" || fail "failed update grub1"
       update_grub2 "$grub2conf" "$grub2def" || fail "failed update grub2"
 
+
+# centos66 images include grub 0.97 which will detect vmtests' ephemeral disk
+# and the install disk which leaves grub configured with two disks.  When
+# vmtest reboots into installed disk, there is only one disk and the grub
+# map is no longer valid.  Here in 00_grub, we switch hd1 to hd0.  MAAS
+# is not affected as their ephemeral image (iscsi or http) is not discovered
+# by grub and therefor the device.map doesn't contain a second device. Cent7
+# has grub2 which uses root by UUID.
+_update_grub_conf:
+ - &update_grub |
+   CONF="/boot/grub2/grub.cfg"
+   [ -f "${CONF}" ] || CONF="/boot/grub/grub.conf"
+   sed -i.curtin -e 's|(hd1,0)|(hd0,0)|g' ${CONF}
+
 late_commands:
- # centos66 images include grub 0.97 which will detect vmtests' ephemeral disk
- # and the install disk which leaves grub configured with two disks.  When
- # vmtest reboots into installed disk, there is only one disk and the grub
- # map is no longer valid.  Here in 00_grub, we switch hd1 to hd0.  MAAS
- # is not affected as their ephemeral image (iscsi or http) is not discovered
- # by grub and therefor the device.map doesn't contain a second device. Cent7
- # has grub2 which uses root by UUID
- 00_grub1_boot: [curtin, in-target, --, sed, -i.curtin, -e,
-                 's|(hd1,0)|(hd0,0)|g', /boot/grub/grub.conf]
+ 00_grub1_boot: [curtin, in-target, --, 'sh', '-c', *update_grub]
  # vmtest wants output to go to serial console so we update grub inside.
  00_grub_serial: [curtin, in-target, --, '/root/curtin-send-console-to-serial']