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Do not use overlayfs to debug container layers #679

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nishakm opened this issue Apr 30, 2020 · 2 comments · Fixed by #771
Closed

Do not use overlayfs to debug container layers #679

nishakm opened this issue Apr 30, 2020 · 2 comments · Fixed by #771
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@rnjudge
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arch Architecture changes are needed feature new feature super Super issue - other issues are linked to this one
Milestone
Release 2.2.0

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@nishakm
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nishakm commented Apr 30, 2020

Describe the Feature
Since tern uses the overlayfs driver to analyze packages layer by layer, it cannot run within a container image without an external mount to a Linux host. Not all hosts are Linux and Docker runs on MacOS and Windows. Hence using an alternative for "debugging" container image filesystems would allow the full operation to take place in a running container.

Use Cases
This is so developers using Windows and MacOS can run tern without needing to install Vagrant.

Implementation Changes
We have to experiment with other methods of combining layers other than using a CoW storage driver.
@nishakm nishakm added feature new feature arch Architecture changes are needed super Super issue - other issues are linked to this one labels Apr 30, 2020
@rnjudge rnjudge mentioned this issue May 6, 2020
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@rnjudge rnjudge added this to the Beta Release milestone May 21, 2020
@nishakm
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nishakm commented May 23, 2020

rsync might be able to merge two directories. It may not know what to do with the whiteout files though.

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nishakm commented May 29, 2020 •
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One possible implementation:

  1. Use rsync to copy the first layer into mergedir
rsync -ac <hash>/contents/ mergedir
  1. For subsequent layers:
    2.1 perform 1.
    2.2 For each file in the layer, check if any files are whiteouts. They will start with .wh. , .wh..wh..opq. or .wh.__dir_opaque.
    2.3 Delete the directory or file with the same name without the whiteout prefixes.

Caveats for this method:

  1. We have to untar without excluding whiteout files.
  2. We have to ignore whiteout files when reporting and caching.

The unfortunate thing about this method is that after analysis of mergedir the whole process needs to start again i.e. all of the previous layers will have to be copied over to mergedir. This is much slower than using the overlayfs graph driver.

@rnjudge rnjudge mentioned this issue Jul 6, 2020
Closed
rnjudge added a commit to rnjudge/tern that referenced this issue Jul 17, 2020
@rnjudge
Amend Dockerfile and docker_run for fuse-overlayfs
5ced9da 
Tern does not currently run within a container image without an external
mount to a linux host. This commit updates the Dockerfile to install
fuse-overlayfs which will allow Tern to run in a container on a
non-linux host. This commit also updates the Dockerfile used for
continuous integration testing. A few notable changes in the Dockerfile
include:

- Change base OS from photon to debian. This is a requirement of
fuse-overlayfs.

- Remove the creation of the hostmount directory, as it is no longer
required for mounting outside of the container.

- Removes the --quiet option in the ENTRYPOINT so the user can see the
default logging behavior.

- Adds the --non-linux command line option to the ENTRYPOINT to enable
fuse-overlayfs as the default mounting behavior.

This commit also updates the docker_run.sh script to no longer mount to
the hostmount directory and adds /dev/fuse as a host device to
enable fuse-overlayfs.

Works towards tern-tools#679

Signed-off-by: Rose Judge <rjudge@vmware.com>
rnjudge added a commit to rnjudge/tern that referenced this issue Jul 17, 2020
@rnjudge
Enable Terns run in a container for non-Linux host
cc7e333 
Tern currently cannot run within a container image without an
external mount to a Linux host. This is due to the dependency on the
Linux filesystem's overlayfs driver that is used to mount the
layers which does not natively exist on Mac or Windows. This commit
makes changes to enable Tern to run on a non-Linux host by using the
FUSE implementation for overlayfs. It does so by adding a --non-linux
command line option. When that option is envoked, instead of mounting to
an external mount point specified by the user, Tern will set the mount
point as the working directory, which happens to be inside the container
when being run on a non-Linux host. When it comes time to mount the
diff layers, Tern will use the non-linux flag to determine if it should
use the fuse-overlayfs or default overlayfs implementation for the
mount.

Resolves tern-tools#679

Signed-off-by: Rose Judge <rjudge@vmware.com>
@rnjudge rnjudge mentioned this issue Jul 17, 2020
Merged
rnjudge added a commit to rnjudge/tern that referenced this issue Jul 17, 2020
@rnjudge
Amend Dockerfile and docker_run for fuse-overlayfs
068c645 
Tern does not currently run within a container image without an external
mount to a linux host. This commit updates the Dockerfile to install
fuse-overlayfs which will allow Tern to run in a container on a
non-linux host. This commit also updates the Dockerfile used for
continuous integration testing. A few notable changes in the Dockerfile
include:

- Change base OS from photon to debian. This is a requirement of
fuse-overlayfs.

- Remove the creation of the hostmount directory, as it is no longer
required for mounting outside of the container.

- Removes the --quiet option in the ENTRYPOINT so the user can see the
default logging behavior.

- Adds the --non-linux command line option to the ENTRYPOINT to enable
fuse-overlayfs as the default mounting behavior.

This commit also updates the docker_run.sh script to no longer mount to
the hostmount directory and adds /dev/fuse as a host device to
enable fuse-overlayfs. Lastly, test_files_touched.py is updated to
account for the changes in how the docker_run script should be invoked.

Works towards tern-tools#679

Signed-off-by: Rose Judge <rjudge@vmware.com>
rnjudge added a commit to rnjudge/tern that referenced this issue Jul 17, 2020
@rnjudge
Enable Terns run in a container for non-Linux host
8a2d39d 
Tern currently cannot run within a container image without an
external mount to a Linux host. This is due to the dependency on the
Linux filesystem's overlayfs driver that is used to mount the
layers which does not natively exist on Mac or Windows. This commit
makes changes to enable Tern to run on a non-Linux host by using the
FUSE implementation for overlayfs. It does so by adding a --non-linux
command line option. When that option is envoked, instead of mounting to
an external mount point specified by the user, Tern will set the mount
point as the working directory, which happens to be inside the container
when being run on a non-Linux host. When it comes time to mount the
diff layers, Tern will use the non-linux flag to determine if it should
use the fuse-overlayfs or default overlayfs implementation for the
mount.

Resolves tern-tools#679

Signed-off-by: Rose Judge <rjudge@vmware.com>
rnjudge added a commit to rnjudge/tern that referenced this issue Jul 24, 2020
@rnjudge
Amend Dockerfile and docker_run for fuse-overlayfs
cf1c707 
Tern does not currently run within a container image without an external
mount to a Linux host. This commit updates the Dockerfile to install
fuse-overlayfs which will allow Tern to run in a container on a
non-Linux host. This commit also updates the Dockerfile used for
continuous integration testing. A few notable changes in the Dockerfile
include:

- Change base OS from photon to debian. This is a requirement of
fuse-overlayfs.
- Remove the creation of the hostmount directory, as it is no longer
required for mounting outside of the container.
- Removes the --quiet option in the ENTRYPOINT so the user can see the
default logging behavior.
- Adds the '--driver fuse' command line option to the ENTRYPOINT to
enable fuse-overlayfs as the default mounting driver.

This commit also updates the docker_run.sh script to no longer mount to
the hostmount directory and adds /dev/fuse as a host device to
enable fuse-overlayfs. test_files_touched.py is updated to
account for the changes in how the docker_run script should be invoked.
Lastly, there is an update to the README that reflects the changes to
commands required to run Tern in a Docker container.

Works towards tern-tools#679

Signed-off-by: Rose Judge <rjudge@vmware.com>
rnjudge added a commit to rnjudge/tern that referenced this issue Jul 24, 2020
@rnjudge
Enable Terns run in a container for non-Linux host
b9ca4ef 
Tern currently cannot run within a container image without an
external mount to a Linux host. This is due to the dependency on the
Linux filesystem's overlayfs driver that is used to mount the
layers which does not natively exist on Mac or Windows. This commit
makes changes to enable Tern to run on a non-Linux host by using the
FUSE implementation for overlayfs when Tern is being run in a container.

First, this commit deprecates the --bind-mount CLI option. Instead, a
--driver CLI option is added that will use the FUSE implementation of
overlayfs to do any mounting in a container, regardless of the host OS.

Since the --bind-mount CLI option is now deprecated, this commit also
makes the necessary updates in cache.py to any mount_dir references and
instead uses the correct working_dir.

Resolves tern-tools#679

Signed-off-by: Rose Judge <rjudge@vmware.com>
rnjudge added a commit to rnjudge/tern that referenced this issue Jul 29, 2020
@rnjudge
Enable Terns run in a container for non-Linux host
e5bc4f8 
Tern currently cannot run within a container image without an
external mount to a Linux host. This is due to the dependency on the
Linux filesystem's overlayfs driver that is used to mount the
layers which does not natively exist on Mac or Windows. This commit
makes changes to enable Tern to run on a non-Linux host by using the
FUSE implementation for overlayfs when Tern is being run in a container.

First, this commit deprecates the --bind-mount CLI option. Instead, a
--driver CLI option is added that will use the FUSE implementation of
overlayfs to do any mounting in a container, regardless of the host OS.

Since the --bind-mount CLI option is now deprecated, this commit also
makes the necessary updates in cache.py to any mount_dir references and
instead uses the correct working_dir.

Resolves tern-tools#679

Signed-off-by: Rose Judge <rjudge@vmware.com>
@rnjudge rnjudge modified the milestones: Beta Release, Release 2.2.0 Jul 30, 2020
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arch Architecture changes are needed feature new feature super Super issue - other issues are linked to this one
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Enable Tern to run in a container for non-Linux host rnjudge/tern
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