ISCSI and Libvirt Clmentine Hayat <clem@lse.epita.fr> 1 GSOC - - PowerPoint PPT Presentation

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ISCSI and Libvirt Clmentine Hayat <clem@lse.epita.fr> 1 GSOC - - PowerPoint PPT Presentation

Feb 06, 2023 104 likes •464 views

ISCSI and Libvirt Clmentine Hayat <clem@lse.epita.fr> 1 GSOC Libvirt 2 What is iSCSI? 3 SCSI standard Command Bus Protocol... 4 5 struct scsi_task * iscsi_read12_task( struct iscsi_context *iscsi, int lun, uint32_t

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ISCSI and Libvirt

Clémentine Hayat <clem@lse.epita.fr>

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GSOC Libvirt

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What is iSCSI?

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SCSI standard

  • Command
  • Bus
  • Protocol...

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struct scsi_task * iscsi_read12_task(struct iscsi_context *iscsi, int lun, uint32_t lba, uint32_t datalen, int blocksize, int rdprotect, int dpo, int fua, int fua_nv, int group_number, iscsi_command_cb cb, void *private_data) { struct scsi_task *task; if (datalen % blocksize != 0) { iscsi_set_error(iscsi, "Datalen:%d is not a multiple of " "the blocksize:%d.", datalen, blocksize); return NULL; } task = scsi_cdb_read12(lba, datalen, blocksize, rdprotect, dpo, fua, fua_nv, group_number); if (task == NULL) { iscsi_set_error(iscsi, "Out-of-memory: Failed to create " "read12 cdb."); return NULL; } if (iscsi_scsi_command_async(iscsi, lun, task, cb, NULL, private_data) != 0) { scsi_free_scsi_task(task); return NULL; } return task; } 6

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How does iSCSI works?

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Discovery Session

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IP addr:127.0.0.1

Hey! Who te? My I is:

iqn.2003-01.org.linux-iscsi.clem.x8664:sn.f39f01319546

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void discovery(struct iscsi_context *iscsi_context, const char *portal) { if (iscsi_connect_sync(iscsi_context, portal) != 0) { printf("iscsi_connect failed. %s\n", iscsi_get_error(iscsi_context)); exit(1); } printf("connected, send login command\n"); iscsi_set_session_type(iscsi_context, ISCSI_SESSION_DISCOVERY); if (iscsi_login_sync(iscsi_context) != 0) { printf("iscsi_login failed : %s\n", iscsi_get_error(iscsi_context)); exit(1); } printf("Logged in to target, send discovery command\n"); struct iscsi_discovery_address *addr = iscsi_discovery_sync(iscsi_context); if (!addr) { printf("failed to send discovery command : %s\n", iscsi_get_error(iscsi_context)); exit(1); } printf("discovery complete, send logout command\n"); if (iscsi_logout_sync(iscsi_context) != 0) { printf("iscsi_logout failed : %s\n", iscsi_get_error(iscsi_context)); exit(1); } printf("disconnect socket\n"); if (iscsi_disconnect(iscsi_context) != 0) { printf("Failed to disconnect old socket\n"); exit(1); } } 10

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Normal Session

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Hey! My i s initiator_iqn. My u d i user. My as pass. Can I e target_iqn? Yes ’re we !

IP addr:127.0.0.1 12

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void normallogin(struct iscsi_context *iscsi_context, char *user, char *passwd, struct client_state *client_state) { printf("Reconnect with normal login to [%s]\n", client_state->target_address); printf("Use targetname [%s] when connecting\n", client_state->target_name); if (iscsi_set_targetname(iscsi_context, client_state->target_name)) { printf("Failed to set target name\n"); exit(1); } if (iscsi_set_session_type(iscsi_context, ISCSI_SESSION_NORMAL) != 0) { printf("Failed to set settion type to normal\n"); exit(1); } if (iscsi_connect_sync(iscsi_context, client_state->target_address) != 0) { printf("iscsi_connect failed : %s\n", iscsi_get_error(iscsi_context)); exit(1); } printf("connected, send login command\n"); iscsi_set_target_username_pwd(iscsi_context, user, passwd); if (iscsi_login_sync(iscsi_context) != 0) { printf("iscsi_login failed\n"); exit(1); } } 13

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Hel! So w re sog? Hey! I ha :

Lun0, Lun1… LunN

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void reportluns(struct iscsi_context *iscsi_context, struct client_state *client_state) { struct scsi_reportluns_list *list; int full_report_size; printf("Logged in normal session, send reportluns\n"); struct scsi_task *scsi_task = iscsi_reportluns_sync(iscsi_context, 0, 16); /* …. */ if (scsi_task->status != SCSI_STATUS_GOOD) { /* …. */} full_report_size = scsi_datain_getfullsize(scsi_task); if (full_report_size > scsi_task->datain.size) { printf("We did not get all the data we need in reportluns, ask again\n"); scsi_free_scsi_task(scsi_task); scsi_task = iscsi_reportluns_sync(iscsi_context, 0, full_report_size); if (!scsi_task) { printf("failed to send reportluns command\n"); scsi_free_scsi_task(scsi_task); exit(10); } } list = scsi_datain_unmarshall(scsi_task); if (!list) {/* …. */} printluns(list, client_state); scsi_free_scsi_task(scsi_task); } 15

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I’m on command on

lun x te.

It ok!

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int testUnitReady(struct iscsi_context *iscsi, int lun) { do { if (!(task = iscsi_testunitready_sync(iscsi, lun))) { /*...*/ } if (task->status != SCSI_STATUS_CHECK_CONDITION || task->sense.key != SCSI_SENSE_UNIT_ATTENTION || task->sense.ascq != SCSI_SENSE_ASCQ_BUS_RESET) break; scsi_free_scsi_task(task); } while (1); if (task->status != SCSI_STATUS_GOOD) { virReportError(VIR_ERR_INTERNAL_ERROR, _("Failed testunitready: %s"), iscsi_get_error(iscsi)); goto cleanup; } ret = 0; /*...*/ } 17

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if (!(task = iscsi_inquiry_sync(ic, lun, 0, 0, 64)) || task->status != SCSI_STATUS_GOOD) { } if (!(inq = scsi_datain_unmarshall(task))) { } printf("inquiry returned type=%d vendor=%s product=%s\n", inq->device_type, inq->vendor_identification, inq->product_identification); scsi_free_scsi_task(task); if (type == SCSI_INQUIRY_PERIPHERAL_DEVICE_TYPE_DIRECT_ACCESS) { struct scsi_readcapacity10 *rc10 = NULL; if (!(task = iscsi_readcapacity10_sync(ic, lun, 0, 0)) || task->status != SCSI_STATUS_GOOD) { } if (!(rc10 = scsi_datain_unmarshall(task))) { } printf("readcapacity10 returned lba=%lu block_size=%lu\n", (unsigned long) rc10->lba, (unsigned long) rc10->block_size); size = rc10->block_size; size *= rc10->lba; } 18

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  • lun0
  • iqn1 -lun1

Initiator => target (ip) - -lun0

  • iqn2 -lun1
  • lun2

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How does libvirt work?

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  • Storage pool
  • Domain
  • XML
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What already has libvirt?

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  • Storage Pool using iscsiadm

○ And libiscsi ○ And iscsiadm

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What is my Gsoc?

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Storage Pool using libiscsi

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What have I done?

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  • storage pool -domain
  • lun0
  • iqn1 -lun1

Initiator => target (ip) - -lun0

  • iqn2 -lun1
  • lun2

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Add libiscsi to libvirt buildsystem

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Storage Pool commands

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XML d’exemple

<pool type='iscsi-direct'> <name>remote-storage</name> <source> <host name='0.0.0.0'/> <device path='iqn.2003-01.org.linux-iscsi.clem.x8664:sn.f39f01319546'/> <initiator> <iqn name='iqn.2005-03.org.open-iscsi:clem'/> </initiator> </source> </pool>

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What’s left to do?

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Conclusion

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Links

  • https://github.com/HClem/libvirt
  • https://github.com/HClem/iSCSI-test
  • https://github.com/sahlberg/libiscsi

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Questions?

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