Re: [pve-devel] [PATCH pve-container 1/3] fix #3711: enable delete of LXC container via force option

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

On Wed, Jul 20, 2022 at 04:49:47PM +0200, Stefan Hrdlicka wrote:
> Make it possible to delete a container whoes underlying storage is no
> longer available. This will just write an warning instead of dying.

"no longer available" != "throws errors" (see below (*))

> 
> Without setting the option force-remove-storage=1 a delete will still
> fail, like it did before the changes. With this option set it will try to
> delete the volume from the storage. If this fails it writes a warning.
> 
> Signed-off-by: Stefan Hrdlicka <s.hrdlicka@proxmox.com>
> ---
>  src/PVE/API2/LXC.pm |  8 ++++++++
>  src/PVE/LXC.pm      | 20 +++++++++++++++-----
>  2 files changed, 23 insertions(+), 5 deletions(-)
> 
> diff --git a/src/PVE/API2/LXC.pm b/src/PVE/API2/LXC.pm
> index 589f96f..4d785c9 100644
> --- a/src/PVE/API2/LXC.pm
> +++ b/src/PVE/API2/LXC.pm
> @@ -697,6 +697,13 @@ __PACKAGE__->register_method({
>  		    ." enabled storages which are not referenced in the config.",
>  		optional => 1,
>  	    },
> +	    'force-remove-storage' => {

This name is a bit confusing as instead of enforcing removal you're
actually ignoring the case where removal *fails*, iow.: you allow *not*
removing data.

The `create_vm` call has an `ignore-unpack-errors` parameter, so maybe
`ignore-storage-errors` would work here. (And renaming all the
$variables accordingly.)

> +		type => 'boolean',
> +		description => 'If set, this will ignore errors when trying to remove LXC'

(*) when documenting it as ignoring errors, I would not expect it to
distinguish between unavailable storages and _other_ errors happening.

Side note: Almost all our API docs just refer to them as 'containers',
the 'LXC' portion can be dropped here.

> +		    . ' container storage.',
> +		default => 0,
> +		optional => 1,
> +	    }
>  	},
>      },
>      returns => {
> @@ -758,6 +765,7 @@ __PACKAGE__->register_method({
>  		$conf,
>  		{ lock => 'destroyed' },
>  		$param->{'destroy-unreferenced-disks'},
> +		$param->{'force-remove-storage'},
>  	    );
>  
>  	    PVE::AccessControl::remove_vm_access($vmid);
> diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
> index fe63087..74c8d17 100644
> --- a/src/PVE/LXC.pm
> +++ b/src/PVE/LXC.pm
> @@ -848,13 +848,22 @@ sub get_primary_ips {
>  }
>  
>  sub delete_mountpoint_volume {
> -    my ($storage_cfg, $vmid, $volume) = @_;
> +    my ($storage_cfg, $vmid, $volume, $force_remove_storage) = @_;
>  
>      return if PVE::LXC::Config->classify_mountpoint($volume) ne 'volume';
>  
> -    my ($vtype, $name, $owner) = PVE::Storage::parse_volname($storage_cfg, $volume);
> +    my ($vtype, $name, $owner);
> +    eval {
> +	($vtype, $name, $owner) = PVE::Storage::parse_volname($storage_cfg, $volume);
> +    };

^ It is not clear to me why you'd cover this, but not the `vdisk_free`
below, unless you're trying to catch only specific errors (but this is
not specific enough...)

I think this sub can be left unchanged and instead the
`delete_mountpoint_volume()` call itself could be wrapped in an
`eval{}` instead.

>  
> -    if ($vmid == $owner) {
> +    if (!$force_remove_storage && $@) {
> +	die $@;
> +    } elsif ($@) {
> +	# $force_remove_storage == true is implied here
> +	warn "storage not available, can't remove $volume disk image, continuing!\n"
> +	    . "error: $@\n";
> +    } elsif ($vmid == $owner) {
>  	PVE::Storage::vdisk_free($storage_cfg, $volume);
>      } else {
>  	warn "ignore deletion of '$volume', CT $vmid isn't the owner!\n";
> @@ -862,7 +871,8 @@ sub delete_mountpoint_volume {
>  }
>  
>  sub destroy_lxc_container {
> -    my ($storage_cfg, $vmid, $conf, $replacement_conf, $purge_unreferenced) = @_;
> +    my ($storage_cfg, $vmid, $conf, $replacement_conf,
> +	$purge_unreferenced, $force_remove_storage) = @_;
>  
>      my $volids = {};
>      my $remove_volume = sub {
> @@ -873,7 +883,7 @@ sub destroy_lxc_container {
>  	return if $volids->{$volume};
>  	$volids->{$volume} = 1;
>  
> -	delete_mountpoint_volume($storage_cfg, $vmid, $volume);
> +	delete_mountpoint_volume($storage_cfg, $vmid, $volume, $force_remove_storage);

So I think I'd just put an `eval{}` here, not pass the parameter
through, and just `die $@ if $@ && !$ignore_storage_errrors` afterwards.

>      };
>      PVE::LXC::Config->foreach_volume_full($conf, {include_unused => 1}, $remove_volume);
>  
> -- 
> 2.30.2