** Description changed: - The symptom is similar to bug 1611074 but the cause is different. In - this case it seems there is an error accessing /dev/sdb1 when lsblk is - run, possibly because sgdisk isn't done creating the partition. The - specific error message is "/dev/sdb1: not a block device." A simple wait - and retry here may resolve the issue. + === Begin SRU Template === + [Impact] + There is a race condition that occurs when cloud-init tries to partition a + block device (/dev/sdb) and then put a filesystem on a partition on it. It is + possible that cloud-init tries to run mkfs on /dev/sdb1 after partitioning the + device /dev/sdb but before the partition device node '/dev/sdb1' exists. + + When this race condition occurs, cloud-init will fail to make the "ephemeral" + device available to the user on Azure. + + [Test Case] + A reliable reproduce test case is hard to come by here. The failure case + is believed to be well understood. + + [Regression Potential] + There should be very little chance for regression, as essentially all the change + does is change: + + 1. sgdisk -n 1:0:0 /dev/sdb + 2. mkfs.ext4 /dev/sdb1 + + to + + 1. sgdisk -n 1:0:0 /dev/sdb + 1a udevadm settle + 1b blockdev --rereadpt + 1c usdevadm settle + 2. mkfs.ext4 /dev/sdb1 + + The steps '1b' and '1c' above are not necessary, but were present already in + the method. They serve here as additional wait. + + [Other Info] + The change that fixes this is viewable at [1]. For context, viewin all of + cc_disk_setup.py [2]. Basically we just add a call to read_parttbl [3] to + exec_mkpart_gpt after invoking a sgdisk command that partitions a disk. + read_partbl basically does a udevadm settle which fixes the race condition that + was seen. + + [1] https://git.launchpad.net/cloud-init/commit/?id=29348af1c889931e8973f8fc8cb090c063316f7a + [2] https://git.launchpad.net/cloud-init/tree/cloudinit/config/cc_disk_setup.py?id=29348af1c889931e8973f8fc8cb090c063316f7a + [3] https://git.launchpad.net/cloud-init/tree/cloudinit/config/cc_disk_setup.py?id=29348af1c889931e8973f8fc8cb090c063316f7a#n674 + + + === End SRU Template === + + + The symptom is similar to bug 1611074 but the cause is different. In this case it seems there is an error accessing /dev/sdb1 when lsblk is run, possibly because sgdisk isn't done creating the partition. The specific error message is "/dev/sdb1: not a block device." A simple wait and retry here may resolve the issue. util.py[DEBUG]: Running command ['/sbin/sgdisk', '-p', '/dev/sdb'] with allowed return codes [0] (shell=False, capture=True) cc_disk_setup.py[DEBUG]: Device partitioning layout matches util.py[DEBUG]: Creating partition on /dev/disk/cloud/azure_resource took 0.056 seconds cc_disk_setup.py[DEBUG]: setting up filesystems: [{'filesystem': 'ext4', 'device': 'ephemeral0.1', 'replace_fs': 'ntfs'}] cc_disk_setup.py[DEBUG]: ephemeral0.1 is mapped to disk=/dev/disk/cloud/azure_resource part=1 cc_disk_setup.py[DEBUG]: Creating new filesystem. cc_disk_setup.py[DEBUG]: Checking /dev/sdb against default devices cc_disk_setup.py[DEBUG]: Manual request of partition 1 for /dev/sdb1 cc_disk_setup.py[DEBUG]: Checking device /dev/sdb1 util.py[DEBUG]: Running command ['/sbin/blkid', '-c', '/dev/null', '/dev/sdb1'] with allowed return codes [0, 2] (shell=False, capture=True) cc_disk_setup.py[DEBUG]: Device /dev/sdb1 has None None cc_disk_setup.py[DEBUG]: Device /dev/sdb1 is cleared for formating cc_disk_setup.py[DEBUG]: File system None will be created on /dev/sdb1 util.py[DEBUG]: Running command ['/bin/lsblk', '--pairs', '--output', 'NAME,TYPE,FSTYPE,LABEL', '/dev/sdb1', '--nodeps'] with allowed return codes [0] (shell=False, capture=True) util.py[DEBUG]: Creating fs for /dev/disk/cloud/azure_resource took 0.008 seconds util.py[WARNING]: Failed during filesystem operation#012Failed during disk check for /dev/sdb1#012Unexpected error while running command.#012Command: ['/bin/lsblk', '--pairs', '--output', 'NAME,TYPE,FSTYPE,LABEL', '/dev/sdb1', '--nodeps']#012Exit code: 32#012Reason: -#012Stdout: ''#012Stderr: 'lsblk: /dev/sdb1: not a block device\n'
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1626243 Title: Cloud-init fails to write ext4 filesystem to Azure Ephemeral Drive To manage notifications about this bug go to: https://bugs.launchpad.net/cloud-init/+bug/1626243/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
