BTRBK on CentOS 7: many errors got when dryrunning

[TheNighthawk99]

Hello,
this could not be an issue, but I cannot further investigate.

I installed BTRBK on a CentOS7 system with btrfs file system. When I run btrbk I get these errors:

Use of ?PATTERN? without explicit operator is deprecated at /bin/btrbk line 5128.
Not enough arguments for grep at /bin/btrbk line 2488, near "$vol_root_id)"
Too many arguments for main::eval_quiet at /bin/btrbk line 5129, near "eval_quiet { require Encode; } ? sub "
  (Might be a runaway multi-line ?? string starting on line 5128)
syntax error at /bin/btrbk line 5129, near "eval_quiet { require Encode; } ? sub "
Global symbol "$no_header" requires explicit package name at /bin/btrbk line 5133.
Global symbol "@keys" requires explicit package name at /bin/btrbk line 5133.
Global symbol "$data" requires explicit package name at /bin/btrbk line 5135.
Global symbol "@keys" requires explicit package name at /bin/btrbk line 5137.
Global symbol "%hide_column" requires explicit package name at /bin/btrbk line 5141.
Global symbol "$empty_cell_char" requires explicit package name at /bin/btrbk line 5142.
Global symbol "$termwidth" requires explicit package name at /bin/btrbk line 5144.
Global symbol "%hide_column" requires explicit package name at /bin/btrbk line 5149.
Global symbol "@keys" requires explicit package name at /bin/btrbk line 5149.
Global symbol "$title" requires explicit package name at /bin/btrbk line 5152.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5153.
Global symbol "$title" requires explicit package name at /bin/btrbk line 5153.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5154.
Global symbol "$title" requires explicit package name at /bin/btrbk line 5154.
Global symbol "$no_header" requires explicit package name at /bin/btrbk line 5158.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5161.
Global symbol "$pretty" requires explicit package name at /bin/btrbk line 5163.
Global symbol "%ralign" requires explicit package name at /bin/btrbk line 5165.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5166.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5169.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5171.
Global symbol "$table_spacing" requires explicit package name at /bin/btrbk line 5173.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5175.
Global symbol "$pretty" requires explicit package name at /bin/btrbk line 5178.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5180.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5181.
Global symbol "$table_spacing" requires explicit package name at /bin/btrbk line 5182.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5184.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5195.
Global symbol "$termwidth" requires explicit package name at /bin/btrbk line 5196.
Global symbol "%ralign" requires explicit package name at /bin/btrbk line 5197.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5198.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5201.
Global symbol "$table_spacing" requires explicit package name at /bin/btrbk line 5202.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5204.
Global symbol "%args" requires explicit package name at /bin/btrbk line 5208.
Global symbol "$fh" requires explicit package name at /bin/btrbk line 5209.
syntax error at /bin/btrbk line 5211, near "}"
/bin/btrbk has too many errors.

Here is the btrfs subvolume list / command output:

ID 257 gen 227 top level 5 path root
ID 258 gen 225 top level 5 path home
ID 260 gen 222 top level 257 path var/lib/machines

Here is the fstab file:

#
# /etc/fstab
# Created by anaconda on Sun Oct  3 22:08:05 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=xxxxx     /mnt/btrfs_pool         btrfs   subvolid=5,defaults,noatime,space_cache      0 0
UUID=xxxxx     /                       btrfs   subvol=root,defaults,noatime,space_cache     0 0
UUID=zzzzz     /boot                   xfs     defaults        0 0
UUID=xxxxx     /home                   btrfs   subvol=home,defaults,noatime,space_cache     0 0
UUID=www     swap                    swap    defaults        0 0

The /mnt/btrfs_pool directory has the following structure:

[username@server ~]$ tree /mnt -L 3
/mnt
└── btrfs_pool
    ├── home
    │   └── username
    ├── root
    │   ├── bin -> usr/bin
    │   ├── boot
    │   ├── dev
    │   ├── etc
    │   ├── home
    │   ├── lib -> usr/lib
    │   ├── lib64 -> usr/lib64
    │   ├── media
    │   ├── mnt
    │   ├── opt
    │   ├── proc
    │   ├── root
    │   ├── run
    │   ├── sbin -> usr/sbin
    │   ├── srv
    │   ├── sys
    │   ├── tmp
    │   ├── usr
    │   └── var
    └── _snaps

the _snaps directory is the one choosen for btrbk snapshots.

Finally, this is the btrbk.conf file:

[username@server ~]$ cat /etc/btrbk/btrbk.conf
#
# Example btrbk configuration file
#
#
# Please refer to the btrbk.conf(5) man-page for a complete
# description of all configuration options.
# For more examples, see README.md included with this package.
#
#   btrbk.conf(5): <https://digint.ch/btrbk/doc/btrbk.conf.5.html>
#   README.md:     <https://digint.ch/btrbk/doc/readme.html>
#
# Note that the options can be overridden per volume/subvolume/target
# in the corresponding sections.
#

# Enable transaction log
transaction_log            /var/log/btrbk.log

# Use long timestamp format (includes hour/minute)
timestamp_format           long

# Enable stream buffer. Adding a buffer between the sending and
# receiving side is generally a good idea.
# NOTE: If enabled, make sure to install the "mbuffer" package!
stream_buffer              512m

# Directory in which the btrfs snapshots are created. Relative to
# <volume-directory> of the volume section.
# If not set, the snapshots are created in <volume-directory>.
#
# If you want to set a custom name for the snapshot (and backups),
# use the "snapshot_name" option within the subvolume section.
#
# NOTE: btrbk does not autmatically create this directory, and the
# snapshot creation will fail if it is not present.
#
#snapshot_dir               _btrbk_snap

# Always create snapshots. Set this to "ondemand" to only create
# snapshots if the target volume is reachable. Set this to "no" if
# snapshot creation is done by another instance of btrbk.
#snapshot_create            always

# Perform incremental backups (set to "strict" if you want to prevent
# creation of non-incremental backups if no parent is found).
#incremental                yes

# Specify after what time (in full hours after midnight) backups/
# snapshots are considered as a daily backup/snapshot
preserve_hour_of_day       18

# Specify on which day of week weekly/monthly backups are to be
# preserved.
preserve_day_of_week       sunday

# Preserve all snapshots for a minimum period of time.
#snapshot_preserve_min      1d

# Retention policy for the source snapshots.
#snapshot_preserve          <NN>h <NN>d <NN>w <NN>m <NN>y

# Preserve all backup targets for a minimum period of time.
#target_preserve_min        no

# Retention policy for backup targets:
#target_preserve            <NN>h <NN>d <NN>w <NN>m <NN>y

# Retention policy for archives ("btrbk archive" command):
#archive_preserve_min       no
#archive_preserve           <NN>h <NN>d <NN>w <NN>m <NN>y

# Specify SSH private key for "ssh://" volumes / targets:
ssh_identity              /etc/btrbk/ssh/id_file
ssh_user                   root
#ssh_compression            no
#ssh_cipher_spec            default

# Enable compression for remote btrfs send/receive operations:
#stream_compress            no
#stream_compress_level      default
#stream_compress_threads    default

# Enable lock file support: Ensures that only one instance of btrbk
# can be run at a time.
lockfile                   /var/lock/btrbk.lock

# Don't wait for transaction commit on deletion. Set this to "after"
# or "each" to make sure the deletion of subvolumes is committed to
# disk when btrbk terminates.
#btrfs_commit_delete        no

# Volume section (optional): "volume <volume-directory>"
#
#   <volume-directory>  Base path within a btrfs filesystem
#                       containing the subvolumes to be backuped
#                       (usually the mount-point of a btrfs filesystem
#                       mounted with subvolid=5 option).
#
# Subvolume section: "subvolume <subvolume-name>"
#
#   <subvolume-name>    Subvolume to be backuped, relative to
#                       <volume-directory> in volume section.
#
# Target section: "target <type> <volume-directory>"
#
#   <type>              (optional) type, defaults to "send-receive".
#   <volume-directory>  Directory within a btrfs filesystem
#                       receiving the backups.
#
# NOTE: The parser does not care about indentation, this is only for
# human readability. All options apply to the last section
# encountered, overriding the corresponding option of the upper
# section. This means that the global options must be set on top,
# before any "volume", "subvolume" or "target section.

# Example retention policy:
#
snapshot_preserve_min   14d
snapshot_preserve       28d

target_preserve_min     no
target_preserve         56d 24w *m

# Simple setup: Backup root and home to external disk
#
#snapshot_dir /btrbk_snapshots
#target       /mnt/btr_backup
#subvolume    /
#subvolume    /home

# Complex setup
#
# In order to keep things organized, it is recommended to use "volume"
# sections and mount the top-level subvolume (subvolid=5):
#
#  $ mount -o subvolid=5 /dev/sda1 /mnt/btr_pool
#
# Backup to external disk mounted on /mnt/btr_backup
volume /mnt/btrfs_pool
  # Create snapshots in /mnt/btr_pool/btrbk_snapshots
  snapshot_dir _snaps

  # Target for all subvolume sections:
  #target /mnt/btr_backup

  # Some default btrfs installations (e.g. Ubuntu) use "@" for rootfs
  # (mounted at "/") and "@home" (mounted at "/home"). Note that this
  # is only a naming convention.
  #subvolume @
  subvolume root
  #subvolume home
  #subvolume kvm
    # Use different retention policy for kvm backups:
#    target ssh://target_ip_address/directory_name/server_name
#    target_preserve 7d 4w


# Backup data to external disk as well as remote host
#volume /mnt/btr_data
#  subvolume  data
    # Always create snapshot, even if targets are unreachable
#    snapshot_create always
#    target /mnt/btr_backup
#    target ssh://backup.my-remote-host.com/mnt/btr_backup

# Backup from remote host, with different naming
#volume ssh://my-remote-host.com/mnt/btr_pool
#  subvolume data_0
#    snapshot_dir   snapshots/btrbk
#    snapshot_name  data_main
#    target /mnt/btr_backup/my-remote-host.com
#

# Resume backups from remote host which runs its own btrbk instance
# creating snapshots for "home" in "/mnt/btr_pool/btrbk_snapshots".
#volume ssh://my-remote-host.com/mnt/btr_pool
#  snapshot_dir           btrbk_snapshots
#  snapshot_create        no
#  snapshot_preserve_min  all
#  subvolume home
#    target /mnt/btr_backup/my-remote-host.com

I have other btrbk installation on Ubuntu Servers and they work, not in CentOS. Does anyone of you able to run on CentOS systems?
At this point I cannot understand how to proceed further.

Thank you.

[digint]

Looks like CentOS does not run btrbk as a perl script. Maybe related to #307. Does it help if you change the shabang (like here: 175049f)?

[TheNighthawk99]

Looks like CentOS does not run btrbk as a perl script. Maybe related to #307. Does it help if you change the shabang (like here: 175049f)?

Hello, thanks your reply.
perl interpreter is in the /usr/bin directory. Here is the output:

[username@server btrbk]$ ls -l /usr/bin/perl
-rwxr-xr-x. 2 root root 11408 Feb  2  2021 /usr/bin/perl
[username@server btrbk]$

Also with this command:

[username@server btrbk]$ which perl
/usr/bin/perl
[username@server btrbk]$

I have also change the shabang as suggested in the 175049f commit.
I get the same long list error.

I don't know how to investigate further. I installed btrbk not with the CentOS repository, but from the version downloaded throught git from this github repository.
Thank you.

[TheNighthawk99]

Ok, I have an update.
Instead of installing the most recent version available here, I played with the 0.25.1, which comes by default with CentOS 7.
Don't know why, but it looks like working, except for the remote backup, where I get this error:

ERROR: Failed to parse subvolume list (unsupported btrfs-progs) for: <remote_ip_address>:/backups/server-name-bkpdir
Offending line: ID 256 gen 902 cgen 8 top level 5 parent_uuid -                                    received_uuid -                                    uuid XXXXX path <FS_TREE>/raspberry01

As far as I understand, a conflict in the btrfs-progs version: in CentOS I have 4.9.1, while at the remote target I have 5.4.1.
Is it really this the issue?

[digint]

I think the issue is ancient perl version in CentOS 7 (according to pkgs.org it's 5.16.3: https://pkgs.org/download/perl).

Can you please provide me the exact btrbk version you were running (commit hash if running masater branch), so that I can match the error lines with the code.
Probably it's some code construct which is not understood correctly and easily fixable.

[TheNighthawk99]

I think the issue is ancient perl version in CentOS 7 (according to pkgs.org it's 5.16.3: https://pkgs.org/download/perl).

Can you please provide me the exact btrbk version you were running (commit hash if running masater branch), so that I can match the error lines with the code. Probably it's some code construct which is not understood correctly and easily fixable.

I am not a GIT expert, anyway, this is the output:

[username@hostname btrbk]$ git rev-parse HEAD
c5273a8745fa60fc52b3180fa210ec3048e6a419

[username@hostname btrbk]$ git log
commit c5273a8745fa60fc52b3180fa210ec3048e6a419
Author: znerol <[email protected]>
Date:   Mon Nov 1 14:27:50 2021 +0100

    documentation: fix openssh website URL

Is the information you need to investigate? If negative, let me know.
Thanks a lot.

[TheNighthawk99]

Ok, just installed PERL v.5.34.0 from source, it works. Other test to come, but I was able to take snapshots and transfer to target on an Ubuntu server.
If you need more information let me know.
Thank you for now.