Re: [pbs-devel] [PATCH proxmox-backup v12 12/26] add auto-mounting for removable datastores

["Fabian Grünbichler" <f.gruenbichler@proxmox.com>]

On September 4, 2024 4:11 pm, Hannes Laimer wrote:
> Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
> ---
>  debian/proxmox-backup-server.install        |  1 +
>  debian/proxmox-backup-server.udev           |  3 ++
>  etc/Makefile                                |  3 +-
>  etc/removable-device-attach@.service.in     |  8 +++
>  src/bin/proxmox_backup_manager/datastore.rs | 55 ++++++++++++++++++++-
>  5 files changed, 68 insertions(+), 2 deletions(-)
>  create mode 100644 etc/removable-device-attach@.service.in
> 
> diff --git a/debian/proxmox-backup-server.install b/debian/proxmox-backup-server.install
> index ef1e9ba1..34bfc454 100644
> --- a/debian/proxmox-backup-server.install
> +++ b/debian/proxmox-backup-server.install
> @@ -4,6 +4,7 @@ etc/proxmox-backup-daily-update.service /lib/systemd/system/
>  etc/proxmox-backup-daily-update.timer /lib/systemd/system/
>  etc/proxmox-backup-proxy.service /lib/systemd/system/
>  etc/proxmox-backup.service /lib/systemd/system/
> +etc/removable-device-attach@.service /lib/systemd/system/
>  usr/bin/pmt
>  usr/bin/pmtx
>  usr/bin/proxmox-tape
> diff --git a/debian/proxmox-backup-server.udev b/debian/proxmox-backup-server.udev
> index afdfb2bc..e21b8bc7 100644
> --- a/debian/proxmox-backup-server.udev
> +++ b/debian/proxmox-backup-server.udev
> @@ -16,3 +16,6 @@ SUBSYSTEM=="scsi_generic", SUBSYSTEMS=="scsi", ATTRS{type}=="1", ENV{ID_SCSI_SER
>    SYMLINK+="tape/by-id/scsi-$env{ID_SCSI_SERIAL}-sg"
>  
>  LABEL="persistent_storage_tape_end"
> +
> +# triggers the mounting of a removable device
> +ACTION=="add", SUBSYSTEM=="block", ENV{ID_FS_UUID}!="", TAG+="systemd", ENV{SYSTEMD_WANTS}="removable-device-attach@$env{ID_FS_UUID}"

so this adds a Wants on our new unit for all block devices with an FS
UUID set?

> \ No newline at end of file
> diff --git a/etc/Makefile b/etc/Makefile
> index 42f639f6..730de4f8 100644
> --- a/etc/Makefile
> +++ b/etc/Makefile
> @@ -7,7 +7,8 @@ DYNAMIC_UNITS := \
>  	proxmox-backup-banner.service \
>  	proxmox-backup-daily-update.service \
>  	proxmox-backup.service \
> -	proxmox-backup-proxy.service
> +	proxmox-backup-proxy.service \
> +	removable-device-attach@.service
>  
>  all: $(UNITS) $(DYNAMIC_UNITS) pbs-enterprise.list
>  
> diff --git a/etc/removable-device-attach@.service.in b/etc/removable-device-attach@.service.in
> new file mode 100644
> index 00000000..e10d1ea3
> --- /dev/null
> +++ b/etc/removable-device-attach@.service.in

why is this `.in` / a dynamic unit?

> @@ -0,0 +1,8 @@
> +[Unit]
> +Description=Try to mount the removable device of a datastore with uuid '%i'.
> +After=proxmox-backup-proxy.service
> +Requires=proxmox-backup-proxy.service
> +
> +[Service]
> +Type=simple
> +ExecStart=/usr/sbin/proxmox-backup-manager datastore uuid-mount %i

does this really need to be a custom command?

> diff --git a/src/bin/proxmox_backup_manager/datastore.rs b/src/bin/proxmox_backup_manager/datastore.rs
> index f2795b39..e74c8537 100644
> --- a/src/bin/proxmox_backup_manager/datastore.rs
> +++ b/src/bin/proxmox_backup_manager/datastore.rs
> @@ -1,4 +1,4 @@
> -use anyhow::{format_err, Error};
> +use anyhow::{bail, format_err, Error};
>  use serde_json::Value;
>  
>  use proxmox_router::{cli::*, ApiHandler, RpcEnvironment};
> @@ -195,6 +195,55 @@ async fn delete_datastore(mut param: Value, rpcenv: &mut dyn RpcEnvironment) ->
>      Ok(())
>  }
>  
> +#[api(
> +    protected: true,
> +    input: {
> +        properties: {
> +            uuid: {
> +                type: String,
> +                description: "The UUID of the device that should be mounted",
> +            },
> +            "output-format": {
> +                schema: OUTPUT_FORMAT,
> +                optional: true,
> +            },
> +        },
> +    },
> +)]
> +/// Try mounting a removable datastore given the UUID.
> +async fn uuid_mount(param: Value, rpcenv: &mut dyn RpcEnvironment) -> Result<Value, Error> {
> +    let uuid = param["uuid"]
> +        .as_str()
> +        .ok_or_else(|| format_err!("uuid has to be specified"))?;
> +
> +    let info = &api2::config::datastore::API_METHOD_LIST_DATASTORES;
> +    let data: Value = match info.handler {
> +        ApiHandler::Sync(handler) => (handler)(serde_json::json!({}), info, rpcenv)?,
> +        _ => unreachable!(),
> +    };
> +
> +    let store_name = data.as_array().and_then(|list| {
> +        list.iter()
> +            .filter_map(Value::as_object)
> +            .find(|store| store.get("backing-device").map_or(false, |d| d.eq(&uuid)))
> +            .and_then(|s| s.get("name").and_then(Value::as_str))
> +    });

wouldn't it be easier to just call

let config = pbs_config::datastore::config()?;
if let Some(store) = config.convert_to_typed_array("datastore")?.into_iter().find(...) {
    ... store.name
}

if we stay with this approach?

> +
> +    if let Some(store_name) = store_name {
> +        let info = &api2::admin::datastore::API_METHOD_MOUNT;
> +        let mount_param = serde_json::json!({
> +            "store": store_name,
> +        });
> +        let result = match info.handler {
> +            ApiHandler::Sync(handler) => (handler)(mount_param, info, rpcenv)?,
> +            _ => unreachable!(),
> +        };
> +        crate::wait_for_local_worker(result.as_str().unwrap()).await?;
> +        return Ok(Value::Null);
> +    }
> +    bail!("'{uuid}' is not associated with any datastore")

if this triggers for all block devices, isn't it kinda noisy? or am I
missing some point where additional filtering takes place..

> +}
> +
>  pub fn datastore_commands() -> CommandLineInterface {
>      let cmd_def = CliCommandMap::new()
>          .insert("list", CliCommand::new(&API_METHOD_LIST_DATASTORES))
> @@ -240,6 +289,10 @@ pub fn datastore_commands() -> CommandLineInterface {
>                      pbs_config::datastore::complete_calendar_event,
>                  ),
>          )
> +        .insert(
> +            "uuid-mount",
> +            CliCommand::new(&API_METHOD_UUID_MOUNT).arg_param(&["uuid"]),
> +        )
>          .insert(
>              "remove",
>              CliCommand::new(&API_METHOD_DELETE_DATASTORE)
> -- 
> 2.39.2
> 
> 
> 
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> 
> 


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