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Support for CIM layer writer #29

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ambarve
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@ambarve ambarve commented Nov 3, 2021

This commit adds a new cimfs differ that will in turn call the cim layer writer from
hcsshim to write container image layers in the CIM format.

Signed-off-by: Amit Barve ambarve@microsoft.com

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@dcantah
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dcantah commented Jan 6, 2022

@ambarve What's the status here?

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Changes LGTM, one question

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@msscotb msscotb left a comment

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Initial comments. Not finishe

}
}
}
buf.Flush()
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Why flush per file?

return 0, err
}
reparse := encodeReparsePointFromTarHeader(hdr)
// If reparse point flag is set but reparse buffer is empty remove the flag.
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I think reparsepoints without a reparse buffer can still be valid, for instance tombstones. Is this behavior the same for NTFS layer extraction?

break
}
if ahdr.Typeflag != tar.TypeReg || !strings.HasPrefix(ahdr.Name, hdr.Name+":") {
hdr = ahdr
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Where is the io.Copy for the primary data stream?

katiewasnothere pushed a commit that referenced this pull request Mar 2, 2022
In linux kernel, the umount writable-mountpoint will try to do sync-fs
to make sure that the dirty pages to the underlying filesystems. The many
number of umount actions in the same time maybe introduce performance
issue in IOPS limited disk.

When CRI-plugin creates container, it will temp-mount rootfs to read
that UID/GID info for entrypoint. Basically, the rootfs is writable
snapshotter and then after read, umount will invoke sync-fs action.

For example, using overlayfs on ext4 and use bcc-tools to monitor
ext4_sync_fs call.

```
// uname -a
Linux chaofan 5.13.0-27-generic #29~20.04.1-Ubuntu SMP Fri Jan 14 00:32:30 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

// open terminal 1
kubectl run --image=nginx --image-pull-policy=IfNotPresent nginx-pod

// open terminal 2
/usr/share/bcc/tools/stackcount ext4_sync_fs -i 1 -v -P

  ext4_sync_fs
  sync_filesystem
  ovl_sync_fs
  __sync_filesystem
  sync_filesystem
  generic_shutdown_super
  kill_anon_super
  deactivate_locked_super
  deactivate_super
  cleanup_mnt
  __cleanup_mnt
  task_work_run
  exit_to_user_mode_prepare
  syscall_exit_to_user_mode
  do_syscall_64
  entry_SYSCALL_64_after_hwframe
  syscall.Syscall.abi0
  github.com/containerd/containerd/mount.unmount
  github.com/containerd/containerd/mount.UnmountAll
  github.com/containerd/containerd/mount.WithTempMount.func2
  github.com/containerd/containerd/mount.WithTempMount
  github.com/containerd/containerd/oci.WithUserID.func1
  github.com/containerd/containerd/oci.WithUser.func1
  github.com/containerd/containerd/oci.ApplyOpts
  github.com/containerd/containerd.WithSpec.func1
  github.com/containerd/containerd.(*Client).NewContainer
  github.com/containerd/containerd/pkg/cri/server.(*criService).CreateContainer
  github.com/containerd/containerd/pkg/cri/server.(*instrumentedService).CreateContainer
  k8s.io/cri-api/pkg/apis/runtime/v1._RuntimeService_CreateContainer_Handler.func1
  github.com/containerd/containerd/services/server.unaryNamespaceInterceptor
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  github.com/grpc-ecosystem/go-grpc-prometheus.(*ServerMetrics).UnaryServerInterceptor.func1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc.UnaryServerInterceptor.func1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1
  k8s.io/cri-api/pkg/apis/runtime/v1._RuntimeService_CreateContainer_Handler
  google.golang.org/grpc.(*Server).processUnaryRPC
  google.golang.org/grpc.(*Server).handleStream
  google.golang.org/grpc.(*Server).serveStreams.func1.2
  runtime.goexit.abi0
    containerd [34771]
    1
```

If there are comming several create requestes, umount actions might
bring high IO pressure on the /var/lib/containerd's underlying disk.

After checkout the kernel code[1], the kernel will not call
__sync_filesystem if the mount is readonly. Based on this, containerd
should use readonly mount to get UID/GID information.

Reference:

* [1] https://elixir.bootlin.com/linux/v5.13/source/fs/sync.c#L61

Closes: containerd#4604

Signed-off-by: Wei Fu <fuweid89@gmail.com>
(cherry picked from commit 813a061)
Signed-off-by: Qiutong Song <qiutongs@google.com>
kevpar pushed a commit that referenced this pull request Mar 30, 2022
In linux kernel, the umount writable-mountpoint will try to do sync-fs
to make sure that the dirty pages to the underlying filesystems. The many
number of umount actions in the same time maybe introduce performance
issue in IOPS limited disk.

When CRI-plugin creates container, it will temp-mount rootfs to read
that UID/GID info for entrypoint. Basically, the rootfs is writable
snapshotter and then after read, umount will invoke sync-fs action.

For example, using overlayfs on ext4 and use bcc-tools to monitor
ext4_sync_fs call.

```
// uname -a
Linux chaofan 5.13.0-27-generic #29~20.04.1-Ubuntu SMP Fri Jan 14 00:32:30 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

// open terminal 1
kubectl run --image=nginx --image-pull-policy=IfNotPresent nginx-pod

// open terminal 2
/usr/share/bcc/tools/stackcount ext4_sync_fs -i 1 -v -P

  ext4_sync_fs
  sync_filesystem
  ovl_sync_fs
  __sync_filesystem
  sync_filesystem
  generic_shutdown_super
  kill_anon_super
  deactivate_locked_super
  deactivate_super
  cleanup_mnt
  __cleanup_mnt
  task_work_run
  exit_to_user_mode_prepare
  syscall_exit_to_user_mode
  do_syscall_64
  entry_SYSCALL_64_after_hwframe
  syscall.Syscall.abi0
  github.com/containerd/containerd/mount.unmount
  github.com/containerd/containerd/mount.UnmountAll
  github.com/containerd/containerd/mount.WithTempMount.func2
  github.com/containerd/containerd/mount.WithTempMount
  github.com/containerd/containerd/oci.WithUserID.func1
  github.com/containerd/containerd/oci.WithUser.func1
  github.com/containerd/containerd/oci.ApplyOpts
  github.com/containerd/containerd.WithSpec.func1
  github.com/containerd/containerd.(*Client).NewContainer
  github.com/containerd/containerd/pkg/cri/server.(*criService).CreateContainer
  github.com/containerd/containerd/pkg/cri/server.(*instrumentedService).CreateContainer
  k8s.io/cri-api/pkg/apis/runtime/v1._RuntimeService_CreateContainer_Handler.func1
  github.com/containerd/containerd/services/server.unaryNamespaceInterceptor
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  github.com/grpc-ecosystem/go-grpc-prometheus.(*ServerMetrics).UnaryServerInterceptor.func1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc.UnaryServerInterceptor.func1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1
  k8s.io/cri-api/pkg/apis/runtime/v1._RuntimeService_CreateContainer_Handler
  google.golang.org/grpc.(*Server).processUnaryRPC
  google.golang.org/grpc.(*Server).handleStream
  google.golang.org/grpc.(*Server).serveStreams.func1.2
  runtime.goexit.abi0
    containerd [34771]
    1
```

If there are comming several create requestes, umount actions might
bring high IO pressure on the /var/lib/containerd's underlying disk.

After checkout the kernel code[1], the kernel will not call
__sync_filesystem if the mount is readonly. Based on this, containerd
should use readonly mount to get UID/GID information.

Reference:

* [1] https://elixir.bootlin.com/linux/v5.13/source/fs/sync.c#L61

Closes: containerd#4604

Signed-off-by: Wei Fu <fuweid89@gmail.com>
This commit adds a new cimfs differ that will in turn call the cim layer writer from
hcsshim to write container image layers in the CIM format.

Signed-off-by: Amit Barve <ambarve@microsoft.com>
katiewasnothere pushed a commit that referenced this pull request Apr 22, 2022
In linux kernel, the umount writable-mountpoint will try to do sync-fs
to make sure that the dirty pages to the underlying filesystems. The many
number of umount actions in the same time maybe introduce performance
issue in IOPS limited disk.

When CRI-plugin creates container, it will temp-mount rootfs to read
that UID/GID info for entrypoint. Basically, the rootfs is writable
snapshotter and then after read, umount will invoke sync-fs action.

For example, using overlayfs on ext4 and use bcc-tools to monitor
ext4_sync_fs call.

```
// uname -a
Linux chaofan 5.13.0-27-generic #29~20.04.1-Ubuntu SMP Fri Jan 14 00:32:30 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

// open terminal 1
kubectl run --image=nginx --image-pull-policy=IfNotPresent nginx-pod

// open terminal 2
/usr/share/bcc/tools/stackcount ext4_sync_fs -i 1 -v -P

  ext4_sync_fs
  sync_filesystem
  ovl_sync_fs
  __sync_filesystem
  sync_filesystem
  generic_shutdown_super
  kill_anon_super
  deactivate_locked_super
  deactivate_super
  cleanup_mnt
  __cleanup_mnt
  task_work_run
  exit_to_user_mode_prepare
  syscall_exit_to_user_mode
  do_syscall_64
  entry_SYSCALL_64_after_hwframe
  syscall.Syscall.abi0
  github.com/containerd/containerd/mount.unmount
  github.com/containerd/containerd/mount.UnmountAll
  github.com/containerd/containerd/mount.WithTempMount.func2
  github.com/containerd/containerd/mount.WithTempMount
  github.com/containerd/containerd/oci.WithUserID.func1
  github.com/containerd/containerd/oci.WithUser.func1
  github.com/containerd/containerd/oci.ApplyOpts
  github.com/containerd/containerd.WithSpec.func1
  github.com/containerd/containerd.(*Client).NewContainer
  github.com/containerd/containerd/pkg/cri/server.(*criService).CreateContainer
  github.com/containerd/containerd/pkg/cri/server.(*instrumentedService).CreateContainer
  k8s.io/cri-api/pkg/apis/runtime/v1._RuntimeService_CreateContainer_Handler.func1
  github.com/containerd/containerd/services/server.unaryNamespaceInterceptor
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  github.com/grpc-ecosystem/go-grpc-prometheus.(*ServerMetrics).UnaryServerInterceptor.func1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc.UnaryServerInterceptor.func1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1
  github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1
  k8s.io/cri-api/pkg/apis/runtime/v1._RuntimeService_CreateContainer_Handler
  google.golang.org/grpc.(*Server).processUnaryRPC
  google.golang.org/grpc.(*Server).handleStream
  google.golang.org/grpc.(*Server).serveStreams.func1.2
  runtime.goexit.abi0
    containerd [34771]
    1
```

If there are comming several create requestes, umount actions might
bring high IO pressure on the /var/lib/containerd's underlying disk.

After checkout the kernel code[1], the kernel will not call
__sync_filesystem if the mount is readonly. Based on this, containerd
should use readonly mount to get UID/GID information.

Reference:

* [1] https://elixir.bootlin.com/linux/v5.13/source/fs/sync.c#L61

Closes: containerd#4604

Signed-off-by: Wei Fu <fuweid89@gmail.com>
@msscotb msscotb self-assigned this May 4, 2022
@ambarve ambarve marked this pull request as draft November 2, 2022 18:33
@ambarve
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ambarve commented Jan 18, 2023

We aren't using this fork anymore. Closing this out.

@ambarve ambarve closed this Jan 18, 2023
@ambarve ambarve deleted the cimfs_pr_1 branch June 5, 2023 18:03
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5 participants