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

[Apostolis Stamatis]

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> 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. 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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