ceph-objectstore-tool – modify or examine the state of an OSD¶

Synopsis¶

ceph-objectstore-tool –data-path path to osd [–op list ]

Possible object operations:

(get|set)-bytes [file]
set-(attr|omap) [file]
(get|rm)-attr|omap)
get-omaphdr
set-omaphdr [file]
list-attrs
list-omap
remove|removeall
dump
set-size
clear-data-digest
remove-clone-metadata

Description¶

ceph-objectstore-tool is a tool for modifying the state of an OSD. It facilitates manipulating an object’s content, removing an object, listing the omap, manipulating the omap header, manipulating the omap key, listing object attributes, and manipulating object attribute keys.

ceph-objectstore-tool provides two main modes: (1) a mode that specifies the “–op” argument (for example, ceph-objectstore-tool –data-path $PATH_TO_OSD –op $SELECT_OPERATION [–pgid $PGID] [–dry-run]), and (2) a mode for positional object operations. If the second mode is used, the object can be specified by ID or by the JSON output of the –op list.

ceph-objectstore-tool –data-path path to osd [–pgid $PG_ID ][–op command]

ceph-objectstore-tool –data-path path to osd [ –op list $OBJECT_ID]

Possible -op commands:

* info
* log
* remove
* mkfs
* fsck
* repair
* fuse
* dup
* export
* export-remove
* import
* list
* list-slow-omap
* fix-lost
* list-pgs
* dump-journal
* dump-super
* meta-list
* get-osdmap
* set-osdmap
* get-superblock
* set-superblock
* get-inc-osdmap
* set-inc-osdmap
* mark-complete
* reset-last-complete
* apply-layour-settings
* update-mon-db
* dump-export
* trim-pg-log

Installation¶

The ceph-osd package provides ceph-objectstore-tool.

Examples¶

Modifying Objects¶

These commands modify state of an OSD. The OSD must not be running when ceph-objectstore-tool is used.

Listing Objects and Placement Groups¶

Make sure that the target OSD is down:

systemctl status ceph-osd@$OSD_NUMBER

Identify all objects within an OSD:

ceph-objectstore-tool --data-path $PATH_TO_OSD --op list

Identify all objects within a placement group:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID --op list

Identify the placement group (PG) that an object belongs to:

ceph-objectstore-tool --data-path $PATH_TO_OSD --op list $OBJECT_ID

Fixing Lost Objects¶

Make sure the OSD is down:

systemctl status ceph-osd@OSD_NUMBER

Fix all lost objects:

ceph-objectstore-tool --data-path $PATH_TO_OSD --op fix-lost

Fix all the lost objects within a specified placement group:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID --op fix-lost

Fix a lost object by its identifier:

ceph-objectstore-tool --data-path $PATH_TO_OSD --op fix-lost $OBJECT_ID

Fix legacy lost objects:

ceph-objectstore-tool --data-path $PATH_TO_OSD --op fix-lost

Manipulating an object’s content¶

Make sure that the target OSD is down:
```
systemctl status ceph-osd@$OSD_NUMBER
```
Find the object by listing the objects of the OSD or placement group.
Before setting the bytes on the object, make a backup and a working copy of the object. Here is the syntactic form of that command:
```
ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT get-bytes > $OBJECT_FILE_NAME
```

For example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' get-bytes > zone_info.default.backup

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' get-bytes > zone_info.default.working-copy

The first command creates the back-up copy, and the second command creates the working copy.

Edit the working copy object file.

Set the bytes of the object:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT set-bytes < $OBJECT_FILE_NAME

For example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' set-bytes < zone_info.default.working-copy

Removing an Object¶

Use ceph-objectstore-tool to remove objects. When an object is removed, its contents and references are removed from the placement group (PG).

Remove an object (syntax):

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT remove

Remove an object (example):

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' remove

Listing the Object Map¶

Use the ceph-objectstore-tool to list the contents of the object map (OMAP). The output is a list of keys.

Verify the appropriate OSD is down:

Syntax:

systemctl status ceph-osd@$OSD_NUMBER

Example:

[root@osd ~]# systemctl status ceph-osd@1

List the object map:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT list-omap

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' list-omap

Manipulating the Object Map Header¶

The ceph-objectstore-tool utility will output the object map (OMAP) header with the values associated with the object’s keys.

Note: If using FileStore as the OSD backend object store, then add the –journal-path $PATH_TO_JOURNAL argument when getting or setting the object map header, where the $PATH_TO_JOURNAL variable is the absolute path to the OSD journal; for example /var/lib/ceph/osd/ceph-0/journal.

Prerequisites¶

Having root access to the Ceph OSD node.

Stopping the ceph-osd daemon.

Procedure¶

Verify that the target OSD is down:

Syntax:

systemctl status ceph-osd@$OSD_NUMBER

Example:

[root@osd ~]# systemctl status ceph-osd@1

Get the object map header:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT get-omaphdr > $OBJECT_MAP_FILE_NAME

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}'  get-omaphdr > zone_info.default.omaphdr.txt

Set the object map header:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT get-omaphdr < $OBJECT_MAP_FILE_NAME

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}'  set-omaphdr < zone_info.default.omaphdr.txt

Manipulating the Object Map Key¶

Use the ceph-objectstore-tool utility to change the object map (OMAP) key. You need to provide the data path, the placement group identifier (PG ID), the object, and the key in the OMAP. Note

If using FileStore as the OSD backend object store, then add the –journal-path $PATH_TO_JOURNAL argument when getting, setting or removing the object map key, where the $PATH_TO_JOURNAL variable is the absolute path to the OSD journal; for example /var/lib/ceph/osd/ceph-0/journal.

Prerequisites

Having root access to the Ceph OSD node.

Stopping the ceph-osd daemon.

Procedure

Get the object map key:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT get-omap $KEY > $OBJECT_MAP_FILE_NAME

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}'  get-omap "" > zone_info.default.omap.txt

Set the object map key:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT set-omap $KEY < $OBJECT_MAP_FILE_NAME

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' set-omap "" < zone_info.default.omap.txt

Remove the object map key:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT rm-omap $KEY

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' rm-omap ""

Listing an Object’s Attributes¶

Use the ceph-objectstore-tool utility to list an object’s attributes. The output provides you with the object’s keys and values. Note

If you are using FileStore as the OSD backend object store and the journal is on a different disk, you must add the –journal-path $PATH_TO_JOURNAL argument when listing an object’s attributes, where the $PATH_TO_JOURNAL variable is the absolute path to the OSD journal; for example /var/lib/ceph/osd/ceph-0/journal.

Prerequisites¶

Having root access to the Ceph OSD node.

Stopping the ceph-osd daemon.

Procedure¶

Verify that the target OSD is down:

Syntax:

systemctl status ceph-osd@$OSD_NUMBER

Example:

[root@osd ~]# systemctl status ceph-osd@1

List the object’s attributes:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT list-attrs

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' list-attrs

MANIPULATING THE OBJECT ATTRIBUTE KEY¶

Use the ceph-objectstore-tool utility to change an object’s attributes. To manipulate the object’s attributes you need the data and journal paths, the placement group identifier (PG ID), the object, and the key in the object’s attribute. Note

If you are using FileStore as the OSD backend object store and the journal is on a different disk, you must add the –journal-path $PATH_TO_JOURNAL argument when getting, setting or removing the object’s attributes. Where the $PATH_TO_JOURNAL variable is the absolute path to the OSD journal, for example /var/lib/ceph/osd/ceph-0/journal.

Prerequisites

Having root access to the Ceph OSD node.

Stopping the ceph-osd daemon.

Procedure

Verify that the target OSD is down.

Syntax:

systemctl status ceph-osd@$OSD_NUMBER

Example:

[root@osd ~]# systemctl status ceph-osd@1

Get the object’s attributes:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT get-attrs $KEY > $OBJECT_ATTRS_FILE_NAME

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0  --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' get-attrs "oid" > zone_info.default.attr.txt

Set an object’s attributes:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT  set-attrs $KEY < $OBJECT_ATTRS_FILE_NAME

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' set-attrs "oid" < zone_info.default.attr.txt

Remove an object’s attributes:

Syntax:

ceph-objectstore-tool --data-path $PATH_TO_OSD --pgid $PG_ID $OBJECT rm-attrs $KEY

Example:

[root@osd ~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-0 --pgid 0.1c '{"oid":"zone_info.default","key":"","snapid":-2,"hash":235010478,"max":0,"pool":11,"namespace":""}' rm-attrs "oid"

Options¶

--help¶: produce help message

--type arg¶: Arg is one of [bluestore (default), filestore, memstore]. This option is needed only if the tool can’t tell the type from –data-path.

--data-path arg¶: path to object store, mandatory

--journal-path arg¶: path to journal, use if tool can’t find it

--pgid arg¶: PG id, mandatory for info, log, remove, export, export-remove, mark-complete, trim-pg-log, and mandatory for apply-layout-settings if –pool is not specified

--pool arg¶: Pool name, mandatory for apply-layout-settings if –pgid is not specified

--op arg¶: Arg is one of [info, log, remove, mkfs, fsck, repair, fuse, dup, export, export-remove, import, list, fix-lost, list-pgs, dump-journal, dump-super, meta-list, get-osdmap, set-osdmap, get-superblock, set-superblock, get-inc-osdmap, set-inc-osdmap, mark-complete, reset-last-complete, apply-layout-settings, update-mon-db, dump-export, trim-pg-log]

--epoch arg¶: epoch# for get-osdmap and get-inc-osdmap, the current epoch in use if not specified

--file arg¶: path of file to export, export-remove, import, get-osdmap, set-osdmap, get-superblock, set-superblock, get-inc-osdmap or set-inc-osdmap

--mon-store-path arg¶: path of monstore to update-mon-db

--fsid arg¶: fsid for new store created by mkfs

--target-data-path arg¶: path of target object store (for –op dup)

--mountpoint arg¶: fuse mountpoint

--format arg (=json-pretty)¶: Output format which may be json, json-pretty, xml, xml-pretty

--debug¶: Enable diagnostic output to stderr

--force¶: Ignore some types of errors and proceed with operation - USE WITH CAUTION: CORRUPTION POSSIBLE NOW OR IN THE FUTURE

--skip-journal-replay¶: Disable journal replay

--skip-mount-omap¶: Disable mounting of omap

--head¶: Find head/snapdir when searching for objects by name

--dry-run¶: Don’t modify the objectstore

--namespace arg¶: Specify namespace when searching for objects

--rmtype arg¶: Specify corrupting object removal ‘snapmap’ or ‘nosnapmap’ - TESTING USE ONLY

Error Codes¶

“Mount failed with ‘(11) Resource temporarily unavailable” - This might mean that you have attempted to run ceph-objectstore-tool on a running OSD.

Availability¶

ceph-objectstore-tool is part of Ceph, a massively scalable, open-source, distributed storage system. ceph-objectstore-tool is provided by the package ceph-osd. Refer to the Ceph documentation at htpp://ceph.com/docs for more information.