feat(disk_setup) add timeout

In a cloud environment, sometimes disks will attach while cloud-init is running and get missed. This adds a configurable timeout to wait for those disks. Signed-off-by: Florian Klink <flokli@flokli.de>
canonical · Dec 8, 2023 · eadf16e · eadf16e
1 parent dac62ec
commit eadf16e
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diff --git a/cloudinit/config/cc_disk_setup.py b/cloudinit/config/cc_disk_setup.py
@@ -131,6 +131,13 @@ def alias_to_device(cand):
                 LOG.warning("Invalid disk definition for %s", disk)
                 continue
 
+            if definition.get("timeout"):
+                tmout = int(definition.get("timeout"))
+                missing = util.wait_for_files([disk],
+                                           maxwait=tmout,
+                                           naplen=0.1)
+                if len(missing) > 0:
+                    LOG.warning("Timeout expired waiting for %s" % disk)
             try:
                 LOG.debug("Creating new partition table/disk")
                 util.log_time(

diff --git a/cloudinit/config/schemas/schema-cloud-config-v1.json b/cloudinit/config/schemas/schema-cloud-config-v1.json
@@ -1261,6 +1261,11 @@
                   "type": "boolean",
                   "default": false,
                   "description": "Controls whether this module tries to be safe about writing partition tables or not. If ``overwrite: false`` is set, the device will be checked for a partition table and for a file system and if either is found, the operation will be skipped. If ``overwrite: true`` is set, no checks will be performed. Using ``overwrite: true`` is **dangerous** and can lead to data loss, so double check that the correct device has been specified if using this option. Default: ``false``"
+                },
+                "timeout": {
+                  "type": "integer",
+                  "default": 0,
+                  "description": "Seconds to wait for a disk to appear. If omitted, no wait is performed. This is useful if a cloud provider has late or inconsistent disk attachments and you need a delay."
                 }
               }
             }

diff --git a/doc/examples/cloud-config-disk-setup.txt b/doc/examples/cloud-config-disk-setup.txt
@@ -98,6 +98,7 @@ disk_setup:
 #       table_type: 'mbr'
 #       layout: <LAYOUT|BOOL>
 #       overwrite: <BOOL>
+#       timeout: <INT>
 #
 # Where:
 #   <DEVICE>: The name of the device. 'ephemeralX' and 'swap' are special
@@ -160,6 +161,11 @@ disk_setup:
 #                   done blindly. USE with caution, you can do things you
 #                   really, really don't want to do.
 #
+#   timeout=<INT>: Seconds to wait for a disk to appear. If omitted, no wait
+#               is performed. This is useful if a cloud provider has late or
+#               inconsistent disk attachments and you need a delay.
+#
+#
 #
 # fs_setup: Setup the filesystem
 # ------------------------------