# How to set environment variable in machine-file?

**URL:** <https://discourse.julialang.org/t/how-to-set-environment-variable-in-machine-file/39909>\
**Category:** Julia at Scale\
**Tags:** question\
**Created:** [May 21, 2020, 8:14pm UTC](https://discourse.julialang.org/t/how-to-set-environment-variable-in-machine-file/39909 "2020-05-21T20:14:43Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![zxjroger](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zxjroger/32/11826_2.png) [@zxjroger](https://discourse.julialang.org/u/zxjroger)\
**Post date:** [May 21, 2020, 8:14pm UTC](https://discourse.julialang.org/t/how-to-set-environment-variable-in-machine-file/39909/1 "2020-05-21T20:14:43Z")

</div>

I have a Julia script which computes many linear programming problems using Gurobi+JuMP in parallel. When I test my code on HPC and submit the following slurm script:

```julia
#!/bin/bash
#SBATCH --job-name=xz49
#SBATCH --partition=interactive
#SBATCH --nodes=1
#SBATCH --export=ALL
#SBATCH --ntasks-per-node=10
#SBATCH --mem-per-cpu=4G
#SBATCH --time=00:30:00

julia --machine-file <(srun hostname -s) gurobi.jl

```

I got the following error:

```julia
ERROR: LoadError: On worker 2:
Invalid Gurobi license
error at ./error.jl:33
Env at /home/xz49/.julia/packages/Gurobi/GeYlA/src/grb_env.jl:19
top-level scope at none:0
eval at ./boot.jl:331
#101 at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.4/Distributed/src/process_messages.jl:290
run_work_thunk at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.4/Distributed/src/process_messages.jl:79
run_work_thunk at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.4/Distributed/src/process_messages.jl:88
#94 at ./task.jl:358

...and 9 more exception(s).

```

However, if I change my slurm script to the following, it works fine:

```julia
#!/bin/bash
#SBATCH --job-name=xz49
#SBATCH --partition= interactive
#SBATCH --ntasks=1
#SBATCH --cpus-per-task=10
#SBATCH --threads-per-core=1
#SBATCH --mem-per-cpu=4G
#SBATCH --time=00:30:00

srun julia -p $SLURM_CPUS_PER_TASK gurobi.jl

```

So, both of them should parallel on 10 CPUs on a single node. But the machine-file approach does not work. I wonder how I should set up Gurobi environmental variable in the first case? Also, in the second case, I can utilize hyper-threading by

```julia
srun julia -p $(( 2 * $SLURM_CPUS_PER_TASK )) gurobi.jl

```

so that my Julia script will parallel on 20 physical/virtual CPUs. I wonder how I could achieve this using machine-file? Thank you very much.

---

<div class="post-metadata">

**Author:** ![jishnub](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jishnub/32/33620_2.png) [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Post date:** [May 22, 2020, 5:21am UTC](https://discourse.julialang.org/t/how-to-set-environment-variable-in-machine-file/39909/2 "2020-05-22T05:21:00Z")

</div>

Since you’re using Slurm, have you considered using `ClusterManagers.jl`? In my experience it forwards the environment variables to the workers correctly.