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soc:2009:pravin:journal:bkodebianiscsi [2009/07/18 11:25] less1 |
soc:2009:pravin:journal:bkodebianiscsi [2009/09/25 19:37] (current) less1 |
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| - Executed above commands from inside live CD | - Executed above commands from inside live CD | ||
| - The ''iscsiadm -m discovery'' command did gave output. | - The ''iscsiadm -m discovery'' command did gave output. | ||
| + | <code> | ||
| + | # iscsiadm -m discovery -t st -p 192.168.0.1 | ||
| + | 192.168.0.1:3260,1 iqn.2001-04.com.example:storage.lun1 | ||
| + | </code> | ||
| + | So, the tools do work. but may be they are able to use other files, tools and modules which are not present in initrd.\\ | ||
| + | How to find those dependencies? | ||
| + | ===== Debugging v2 ===== | ||
| + | Finally, added the ''strace'' to initramfs, and now trying find what is the problem because of which iscsiadm is dying\\ | ||
| + | <code> | ||
| + | socket(PF_FILE, SOCK_STREAM, 0) = 3 | ||
| + | connect(3, {sa_family=AF_FILE, path=@"ISCSIADM_ABSTRACT_NAMESPACE"...}, 110) = 0 | ||
| + | write(3, "\n\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 5244) = -1 EPIPE (Broken pipe) | ||
| + | </code> | ||
| + | This is what killing the iscsiadm imatuarly. | ||
| + | ==== Checking the code of open-iscsi ==== | ||
| + | With help of stephana, the likely problem is located at following location | ||
| + | <code> | ||
| + | stefanha: http://git.kernel.org/?p=linux/kernel/git/mnc/open-iscsi.git;a=blob;f=usr/mgmt_ipc.c;h=e784bcac019a84522e62beff1b49b1ca62e37f5a;hb=HEAD | ||
| + | (07/19/2009 04:34:21 PM) stefanha: less1: Perhaps you're hitting this: | ||
| + | (07/19/2009 04:34:27 PM) stefanha: http://git.kernel.org/?p=linux/kernel/git/mnc/open-iscsi.git;a=blob;f=usr/mgmt_ipc.c;h=e784bcac019a84522e62beff1b49b1ca62e37f5a;hb=HEAD#l549 | ||
| + | (07/19/2009 04:34:31 PM) stefanha: if (!mgmt_peeruser(fd, user) || strncmp(user, "root", PEERUSER_MAX)) { | ||
| + | (07/19/2009 04:34:43 PM) stefanha: write(2) will return EPIPE if the UNIX domain socket was closed. | ||
| + | (07/19/2009 04:35:17 PM) stefanha: mgmt_peeruser() is defined here: http://git.kernel.org/?p=linux/kernel/git/mnc/open-iscsi.git;a=blob;f=usr/mgmt_ipc.c;h=e784bcac019a84522e62beff1b49b1ca62e37f5a;hb=HEAD#l342 | ||
| + | (07/19/2009 04:38:15 PM) less1: stefanha: is it checking if I have root privilages? I am not sure if I understand which peeruser credential is it refering. | ||
| + | (07/19/2009 04:40:08 PM) stefanha: Your user name must be "root". | ||
| + | (07/19/2009 04:40:25 PM) stefanha: Otherwise iscsid will not accept commands from the UNIX domain socket. | ||
| + | </code> | ||
| + | === Possible solution : hacking open-iscsi === | ||
| + | | ||
| + | modified the ''iscsiadm'' code so that, it will not fail when username is not ''root''.\\ | ||
| + | With is modification, the discovery part is working, but now there is error at login part. Following is the error. | ||
| + | <code> | ||
| + | connection2:0: Could not create connection due to crc32c loading error. Make sure the crc32c module is build as module into the kernel. | ||
| + | </code> | ||
| + | The first attempt will be to download the kernel module from Live CD of debian after booting it from CD.\\ | ||
| + | --- Doing it | ||
| + | |||
| + | ===== Working Solution ===== | ||
| + | There was need for two extra kernel modules | ||
| + | - libcrc32c.ko | ||
| + | - crc32c.ko | ||
| + | Fetched these modules from live-CD and added them.\\ | ||
| + | There as also need for small sleep after ''iscsiadm --login'' as ''/dev/sda'' was taking little time to appear.\\ | ||
| + | This was handled by adding ''sleep 2''\\ | ||
| + | |||
| + | Two new parameters were introduced | ||
| + | - ''iscsifs=<IP:PORT>'' iscsi server IP and port number | ||
| + | - ''target=<targetname>'' the iscsi target name of the disk (entire name is not needed, some part which can uniquely identify apart from other disks exported at same machine) | ||
| + | |||
| + | ===== Remote ISCSI ===== | ||
| + | |||
| + | Following are the errors that I get when connecting to remote iscsi | ||
| + | <code> | ||
| + | Connection1:0: ping timeout of 5 secs expired, last rx 307737, last ping 308987, now 310237 | ||
| + | Connection1:0: detected conn error (1011) | ||
| + | SQUASHFS error : Unable to read page, block 0x1b392 | ||
| + | Bus error | ||
| + | </code> | ||
| + | Most of these errors are related to timing, and I believe that | ||
| + | these errors are there because of delays in accessing required data. | ||
| + | |||
| + | ===== Target behaviour ===== | ||
| + | sometimes, you may get following error when logging in with iscsiadm | ||
| + | <code> | ||
| + | iscsiadm -m node --targetname "${targetname}" --portal "${ISCSIFS}" --login | ||
| + | records not found!. | ||
| + | </code> | ||
| + | this is because the ${ISCSIFS} is not IP but dnsname. | ||
| + | Dnsname may work with ''iscsiadm -m discovery -t st -p "${ISCSIFS}" '' | ||
| + | but it may verywell fail when same dnsname is given to login. | ||
| + | [[http://groups.google.com/group/open-iscsi/browse_thread/thread/c556508505ecc461|mailing list discussion]] | ||
| + | |||
| + | ==== Solution ==== | ||
| + | Dont use ''--portal "${ISCSIFS}"'' option, use | ||
| + | <code> | ||
| + | iscsiadm -m node --targetname "${targetname}" --login | ||
| + | </code> | ||
