[MESOS-6653] Overlayfs backend may fail to mount the rootfs if both container image and image volume are specified.

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 1.2.0
• Component/s: containerization
• Labels: backend containerizer overlayfs
• Target Version/s: 1.2.0
• Epic Link: Unified Container
• Sprint: Mesosphere Sprint 47, Mesosphere Sprint 48, Mesosphere Sprint 50
• Story Points: 3
• Assignee: Gilbert Song
• Reporter: Gilbert Song
• Shepherd: Jie Yu
• Created: 30/Nov/16 17:54
• Updated: 07/Feb/17 18:19
• Resolved: 26/Jan/17 02:02

Description

Depending on MESOS-6000, we use symlink to shorten the overlayfs mounting arguments. However, if more than one image need to be provisioned (e.g., a container image is specified while image volumes are specified for the same container), the symlink .../backends/overlay/links would fail to be created since it exists already.

Here is a simple log when we hard code overlayfs as our default backend:

[07:02:45] :	 [Step 10/10] [ RUN      ] Nesting/VolumeImageIsolatorTest.ROOT_ImageInVolumeWithRootFilesystem/0
[07:02:46] :	 [Step 10/10] I1127 07:02:46.416021  2919 containerizer.cpp:207] Using isolation: filesystem/linux,volume/image,docker/runtime,network/cni
[07:02:46] :	 [Step 10/10] I1127 07:02:46.419312  2919 linux_launcher.cpp:150] Using /sys/fs/cgroup/freezer as the freezer hierarchy for the Linux launcher
[07:02:46] :	 [Step 10/10] E1127 07:02:46.425336  2919 shell.hpp:107] Command 'hadoop version 2>&1' failed; this is the output:
[07:02:46] :	 [Step 10/10] sh: 1: hadoop: not found
[07:02:46] :	 [Step 10/10] I1127 07:02:46.425379  2919 fetcher.cpp:69] Skipping URI fetcher plugin 'hadoop' as it could not be created: Failed to create HDFS client: Failed to execute 'hadoop version 2>&1'; the command was either not found or exited with a non-zero exit status: 127
[07:02:46] :	 [Step 10/10] I1127 07:02:46.425452  2919 local_puller.cpp:94] Creating local puller with docker registry '/tmp/R6OUei/registry'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.427258  2934 containerizer.cpp:956] Starting container 9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330 for executor 'test_executor' of framework 
[07:02:46] :	 [Step 10/10] I1127 07:02:46.427592  2938 metadata_manager.cpp:167] Looking for image 'test_image_rootfs'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.427774  2936 local_puller.cpp:147] Untarring image 'test_image_rootfs' from '/tmp/R6OUei/registry/test_image_rootfs.tar' to '/tmp/R6OUei/store/staging/9krDz2'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.512070  2933 local_puller.cpp:167] The repositories JSON file for image 'test_image_rootfs' is '{"test_image_rootfs":{"latest":"815b809d588c80fd6ddf4d6ac244ad1c01ae4cbe0f91cc7480e306671ee9c346"}}'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.512279  2933 local_puller.cpp:295] Extracting layer tar ball '/tmp/R6OUei/store/staging/9krDz2/815b809d588c80fd6ddf4d6ac244ad1c01ae4cbe0f91cc7480e306671ee9c346/layer.tar to rootfs '/tmp/R6OUei/store/staging/9krDz2/815b809d588c80fd6ddf4d6ac244ad1c01ae4cbe0f91cc7480e306671ee9c346/rootfs'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.617442  2937 metadata_manager.cpp:155] Successfully cached image 'test_image_rootfs'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.617908  2938 provisioner.cpp:286] Image layers: 1
[07:02:46] :	 [Step 10/10] I1127 07:02:46.617925  2938 provisioner.cpp:296] Should hit here
[07:02:46] :	 [Step 10/10] I1127 07:02:46.617949  2938 provisioner.cpp:315] !!!!: bind
[07:02:46] :	 [Step 10/10] I1127 07:02:46.617959  2938 provisioner.cpp:315] !!!!: overlay
[07:02:46] :	 [Step 10/10] I1127 07:02:46.617967  2938 provisioner.cpp:315] !!!!: copy
[07:02:46] :	 [Step 10/10] I1127 07:02:46.617974  2938 provisioner.cpp:318] Provisioning image rootfs '/mnt/teamcity/temp/buildTmp/Nesting_VolumeImageIsolatorTest_ROOT_ImageInVolumeWithRootFilesystem_0_1fMo0c/provisioner/containers/9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330/backends/overlay/rootfses/c71e83d2-5dbe-4eb7-a2fc-b8cc826771f7' for container 9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330 using overlay backend
[07:02:46] :	 [Step 10/10] I1127 07:02:46.618408  2936 overlay.cpp:175] Created symlink '/mnt/teamcity/temp/buildTmp/Nesting_VolumeImageIsolatorTest_ROOT_ImageInVolumeWithRootFilesystem_0_1fMo0c/provisioner/containers/9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330/backends/overlay/links' -> '/tmp/DQ3blT'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.618472  2936 overlay.cpp:203] Provisioning image rootfs with overlayfs: 'lowerdir=/tmp/DQ3blT/0,upperdir=/mnt/teamcity/temp/buildTmp/Nesting_VolumeImageIsolatorTest_ROOT_ImageInVolumeWithRootFilesystem_0_1fMo0c/provisioner/containers/9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330/backends/overlay/scratch/c71e83d2-5dbe-4eb7-a2fc-b8cc826771f7/upperdir,workdir=/mnt/teamcity/temp/buildTmp/Nesting_VolumeImageIsolatorTest_ROOT_ImageInVolumeWithRootFilesystem_0_1fMo0c/provisioner/containers/9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330/backends/overlay/scratch/c71e83d2-5dbe-4eb7-a2fc-b8cc826771f7/workdir'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.619098  2933 linux.cpp:451] Ignored an image volume for container 9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330
[07:02:46] :	 [Step 10/10] I1127 07:02:46.619745  2938 metadata_manager.cpp:167] Looking for image 'test_image_volume'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.619925  2937 local_puller.cpp:147] Untarring image 'test_image_volume' from '/tmp/R6OUei/registry/test_image_volume.tar' to '/tmp/R6OUei/store/staging/2GNlJO'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.713526  2935 local_puller.cpp:167] The repositories JSON file for image 'test_image_volume' is '{"test_image_volume":{"latest":"815b809d588c80fd6ddf4d6ac244ad1c01ae4cbe0f91cc7480e306671ee9c346"}}'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.713726  2935 local_puller.cpp:295] Extracting layer tar ball '/tmp/R6OUei/store/staging/2GNlJO/815b809d588c80fd6ddf4d6ac244ad1c01ae4cbe0f91cc7480e306671ee9c346/layer.tar to rootfs '/tmp/R6OUei/store/staging/2GNlJO/815b809d588c80fd6ddf4d6ac244ad1c01ae4cbe0f91cc7480e306671ee9c346/rootfs'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.818696  2937 metadata_manager.cpp:155] Successfully cached image 'test_image_volume'
[07:02:46] :	 [Step 10/10] I1127 07:02:46.819169  2934 provisioner.cpp:286] Image layers: 1
[07:02:46] :	 [Step 10/10] I1127 07:02:46.819188  2934 provisioner.cpp:296] Should hit here
[07:02:46] :	 [Step 10/10] I1127 07:02:46.819221  2934 provisioner.cpp:315] !!!!: bind
[07:02:46] :	 [Step 10/10] I1127 07:02:46.819232  2934 provisioner.cpp:315] !!!!: overlay
[07:02:46] :	 [Step 10/10] I1127 07:02:46.819236  2934 provisioner.cpp:315] !!!!: copy
[07:02:46] :	 [Step 10/10] I1127 07:02:46.819241  2934 provisioner.cpp:318] Provisioning image rootfs '/mnt/teamcity/temp/buildTmp/Nesting_VolumeImageIsolatorTest_ROOT_ImageInVolumeWithRootFilesystem_0_1fMo0c/provisioner/containers/9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330/backends/overlay/rootfses/baf632b3-29c5-45e4-9d2e-6f3a2bdd9759' for container 9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330 using overlay backend
[07:02:46] :	 [Step 10/10] ../../src/tests/containerizer/volume_image_isolator_tests.cpp:214: Failure
[07:02:46] :	 [Step 10/10] (launch).failure(): Failed to create symlink '/mnt/teamcity/temp/buildTmp/Nesting_VolumeImageIsolatorTest_ROOT_ImageInVolumeWithRootFilesystem_0_1fMo0c/provisioner/containers/9af6c98a-d9f7-4c89-a5ed-fc7ae2fa1330/backends/overlay/links' -> '/tmp/6dj9IG'
[07:02:46] :	 [Step 10/10] [  FAILED  ] Nesting/VolumeImageIsolatorTest.ROOT_ImageInVolumeWithRootFilesystem/0, where GetParam() = false (919 ms)

We should differenciate the links for different provisioned images.

Issue Links

• is depended upon by: MESOS-5931 Support auto backend in Unified Containerizer.