** Description changed: - When multiple containers (template ubuntu) are created simultaneously - only the first container is successfully created, others fail with - "failed to execute template 'ubuntu'" + ========== SRU justification ============== + 1. Impact: parallel creations of containers with the same template + will result in all but one failing. They should instead run in + parallel without racing in their critical section. + 2. Development fix: don't add '-n' to the flock arguments, which causes + flock to fail instead of waiting. + 3. Stable fix: same as development fix. + 4 Test case: + for i in `seq 10 12`; do + screen -d -m sudo lxc-create -t ubuntu -n p$i + done + ret=0 + while [ $ret -eq 0 ]; do + sleep 1 + pidof bash > /dev/null 2>&1 + ret=$? + done + + while [ `pidof lxc-create > /dev/null 2>&1` ]; do + sleep 1 + done + lxc-ls + # make sure p10, p11, and p12 exist + 5. Regression potential: none + ============================== + + + When multiple containers (template ubuntu) are created simultaneously only the first container is successfully created, others fail with "failed to execute template 'ubuntu'" This is a very common scenario in automated tests. TEST CASE: Run the following script with sudo """ #!/bin/sh MAX=3 echo "Destroying existing containers" for x in $(seq 1 $MAX); do - sudo lxc-destroy -f -n test-lxc-$x & + sudo lxc-destroy -f -n test-lxc-$x & done sleep 10 sudo lxc-list echo "Creating $MAX ubuntu containers" for x in $(seq 1 $MAX); do - echo -n "Creating $x ..." - sudo lxc-create -t ubuntu -n test-lxc-$x & - echo "done" + echo -n "Creating $x ..." + sudo lxc-create -t ubuntu -n test-lxc-$x & + echo "done" done echo "Waiting 30s for test to finish" sleep 30 sudo lxc-list """ ACTUAL RESULT ================================= - $ sudo sh ./lxc-create-concurrent + $ sudo sh ./lxc-create-concurrent Destroying existing containers 'test-lxc-1' does not exist 'test-lxc-2' does not exist 'test-lxc-3' does not exist RUNNING FROZEN STOPPED Creating 3 ubuntu containers Creating 1 ...done Creating 2 ...done Creating 3 ...done Waiting 30s for test to finish No config file specified, using the default config No config file specified, using the default config No config file specified, using the default config debootstrap is /usr/sbin/debootstrap debootstrap is /usr/sbin/debootstrap - Checking cache download in /var/cache/lxc/quantal/rootfs-amd64 ... - Copy /var/cache/lxc/quantal/rootfs-amd64 to /var/lib/lxc/test-lxc-1/rootfs ... + Checking cache download in /var/cache/lxc/quantal/rootfs-amd64 ... + Copy /var/cache/lxc/quantal/rootfs-amd64 to /var/lib/lxc/test-lxc-1/rootfs ... Copying rootfs to /var/lib/lxc/test-lxc-1/rootfs ... failed to execute template 'ubuntu' debootstrap is /usr/sbin/debootstrap failed to execute template 'ubuntu' aborted aborted ## # The default user is 'ubuntu' with password 'ubuntu'! # Use the 'sudo' command to run tasks as root in the container. ## 'ubuntu' template installed 'test-lxc-1' created RUNNING FROZEN STOPPED - test-lxc-1 + test-lxc-1 ================================= ProblemType: Bug DistroRelease: Ubuntu 12.10 Package: lxc 0.8.0~rc1-4ubuntu10 ProcVersionSignature: Ubuntu 3.4.0-3.8-generic 3.4.0 Uname: Linux 3.4.0-3-generic x86_64 ApportVersion: 2.1.1-0ubuntu1 Architecture: amd64 Date: Fri Jun 1 17:32:06 2012 ProcEnviron: - TERM=xterm - PATH=(custom, user) - LANG=en_US.UTF-8 - SHELL=/bin/bash + TERM=xterm + PATH=(custom, user) + LANG=en_US.UTF-8 + SHELL=/bin/bash SourcePackage: lxc UpgradeStatus: Upgraded to quantal on 2012-01-31 (121 days ago)
-- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to lxc in Ubuntu. https://bugs.launchpad.net/bugs/1007483 Title: lxc fails to create containers concurrently To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1007483/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
