I'm experiencing this issue too with artful on c5.large. During the installation of sssd-common 1.15.3-2ubuntu1, the last line of output is "Warning failed to create cache: usr.sbin.sssd" before the instance becomes unresponsive. If I use t2.medium, I don't experience this issue.
Regions tested: us-west-2 and eu-west-1 I do believe that I've experienced this issue without installing sssd, sometimes the machine fails to boot from the initial launch of the AMI. It freezes at "kernel: iscsi: registered transport (iser)" -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1746806 Title: sssd appears to crash AWS c5 and m5 instances, cause 100% CPU Status in cloud-images: New Status in linux package in Ubuntu: Confirmed Status in sssd package in Ubuntu: Confirmed Bug description: After upgrading to the Ubuntu EC2 AMI from 20180126 (specifically ami-79873901 in us-west-2) we have seen sssd hard locking c5 and m5 EC2 instances after starting the service and CPU goes to 100%. We do not experience this issue with t2 or c4 instance types and we do not see this issue on any instance types using Ubuntu Cloud images from 20180109 or before. I have verified that this is kernel related as I booted an image that we created using the Ubuntu cloud image from 20180109 which works fine on a c5. I then did a "apt update && apt install --only-upgrade linux-aws && systemctl disable sssd", rebooted the server, verified I was on the new kernel and started sssd with "systemctl start sssd" and the EC2 instance froze and Cloudwatch CPU usage for that instance went to 100%. I haven't been able to find much in the syslog, kern.log, journalctl logs, etc. The only thing I have been able to find is that when this happens I tend to see "^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@" in the syslog and sssd log files. I have attached several log files and the output of a "apport-bug /usr/sbin/sssd". Let me know if you need anything else to help track this down. Thanks, Paul To manage notifications about this bug go to: https://bugs.launchpad.net/cloud-images/+bug/1746806/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : firstname.lastname@example.org Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp