[lustre-discuss] lustreapi not found when compiling sample C program

[Andreas Dilger]

Why not build packages and install them properly?  There are a few pages on https://wiki.lustre.org/ for this (which should be updated if they are missing some info), but the TLDR to build a client is to run in the Lustre Git checkout tree:

    sh autogen.sh
    ./configure --disable-tests --disable-server
    make debs

(or "make rpms" for RH/SLES) and then install the resulting packages should work for most people if the pre-compiled packages do not.  This avoids copying the files around, ensures that those files are cleaned up when new packages are installed/removed, has proper dependencies, etc.

Cheers, Andreas

On Jul 10, 2024, at 15:55, Apostolis Stamatis via lustre-discuss <lustre-discuss at lists.lustre.org<mailto:lustre-discuss at lists.lustre.org>> wrote:

Hello all,

Sharing an update on this issue to help anyone in the future encountering similar problems.

The first solution I tried was to abandon the installation from source and install the deb packages. This fixed the issues with the linker and the compiler and I was able to use the C api, because it put the files on the default paths for gcc and ld. However, this caused other issues when I went to mount the filesystem (eg modprobe lustre not working), to my understanding caused by the deb packages being built for a slightly different kernel version.

So this made me go back to installing from source and building the deb packages myself. In order to fix my path errors, I manually copied the required files to the default paths used by gcc and ld. I understand this is not necessary, as I can also add the paths when compiling. However this made me wonder whether there is a way to directly generate/copy the include files/libraries on the system defaults ? Looked through the docs but couldn't find anything on this.

In any case, what I needed to copy for my use case (there might be additional files for completeness which I didn't need, not sure):

cp lustre-release/lustre/include/lustre/*.h /usr/include/lustre/

cp lustre-release/lustre/include/uapi/linux/lustre/*.h /usr/include/linux/lustre/

cp lustre-release/debian/lustre-dev/usr/lib/* /usr/lib/

After that the simple `gcc test.c -llustreapi` worked

Thanks for the help, feel free to add anything you might think is useful (potentially a better way to do what I described)

Regards,

Apostolis


On 4/7/24 19:13, Apostolis Stamatis via lustre-discuss wrote:
Thanks for the help Andreas, indeed installing the lustre-dev and lustre-client-utils packages solved the issue with the lustreapi library.

However I am still getting an error:

```

/usr/bin/ld: /tmp/cceAX1ZW.o: in function `main':
test_file.c:(.text+0x37): undefined reference to `llapi_file_create'
collect2: error: ld returned 1 exit status

```

This leads me to believe I am doing something else wrong (potentially with the includes?).

Anyone with any input on what the issue might be or alternatively the steps they have followed to use the C lustre api?

Cheers, Apostolis


On 8/6/24 21:19, Andreas Dilger wrote:
On Jun 8, 2024, at 08:14, Apostolis Stamatis via lustre-discuss <lustre-discuss at lists.lustre.org<mailto:lustre-discuss at lists.lustre.org>> wrote:

Hello everyone,

I am trying to use the C api for lustre, using Ubuntu 22.04, kernel version 5.15.0-107 and lustre client modules version 2.15.4
I am building lustre from source with the following steps (removed some junk like git clone and cd) (mainly from the guide https://metebalci.com/blog/lustre-2.15.4-on-rhel-8.9-and-ubuntu-22.04/)

It would be great to copy this page to wiki.lustre.org<http://wiki.lustre.org>. It is a bit ironic that this page is mentioning that the wiki is outdated, but then proceeds to not update the wiki with new content...

```
sudo apt install build-essential libtool pkg-config flex bison libpython3-dev libmount-dev libaio-dev libssl-dev libnl-genl-3-dev libkeyutils-dev libyaml-dev libreadline-dev module-assistant debhelper dpatch libsnmp-dev mpi-default-dev quilt swig
sh autogen.sh
./configure --disable-server
make dkms-debs
sudo dpkg -i debs/lustre-client-modules-dkms_2.15.4-1_amd64.deb
sudo apt --fix-broken install
sudo dpkg -i debs/lustre-client-utils_2.15.4-1_amd64.deb
```

The client works as expected and can mount and modify the filesystem.
However when I try to compile the sample program using gcc v 11.4.0 with the command
`gcc -I/usr/src/lustre-client-modules-2.15.4/lustre/include -I/usr/src/lustre-client-modules-2.15.4/lustre/include/uapi/ -I/usr/src/lustre-client-modules-2.15.4/lustre/include/lustre -llustreapi test_file.c -o test`
I get the error `/usr/bin/ld: cannot find -llustreapi: No such file or directory`

After trying to find the lustreapi library manually, indeed I can't seem to find it anywhere

According to the most recent build on the b2_15 branch on Ununtu 22.04 https://build.whamcloud.com/job/lustre-b2_15/87/arch=x86_64,build_type=client,distro=ubuntu2204,ib_stack=inkernel/

There is a "lustre-dev" package built, and it looks like that this would contain the library files, "This package provides development libraries for the Lustre filesystem."

Cheers, Andreas
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Cheers, Andreas
--
Andreas Dilger
Lustre Principal Architect
Whamcloud







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