opam init fails building "ocaml-system" : bwrap: Creating new namespace failed: Operation not permitted

[sebma]

Hi,
opam init fails building ocaml-system because of a bwrap error :

root@pc1:~# opam config report
[WARNING] Running as root is not recommended
# opam config report
# opam-version      2.0.4
# self-upgrade      no
# system            arch=x86_64 os=linux os-distribution=ubuntu os-version=16.04
[ERROR] Opam has not been initialised, please run `opam init'
# read-state        OpamStd.OpamSys.Exit(50)
root@pc1:~# opam init -a
[WARNING] Running as root is not recommended
[NOTE] Will configure from built-in defaults.
Checking for available remotes: rsync and local, git.
  - you won't be able to use mercurial repositories unless you install the hg command on your system.
  - you won't be able to use darcs repositories unless you install the darcs command on your system.

[WARNING] Recommended dependencies -- most packages rely on these:
  - make
  - m4

<><> Fetching repository information ><><><><><><><><><><><><><><><><><><><><><>
[default] Initialised
default (at https://opam.ocaml.org):
    [WARNING] opam is out-of-date. Please consider updating it (https://opam.ocaml.org/doc/Install.html)


User configuration:
  Updating ~/.profile.
[NOTE] Make sure that ~/.profile is well sourced in your ~/.bashrc.


<><> Creating initial switch (ocaml-system>=4.02.3) <><><><><><><><><><><><><><>

<><> Gathering sources ><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
[ocaml-system.4.02.3/gen_ocaml_config.ml.in] downloaded from https://opam.ocaml.org/cache
[ocaml-config.1/gen_ocaml_config.ml.in] downloaded from https://opam.ocaml.org/cache
[ocaml-config.1/ocaml-config.install] downloaded from https://opam.ocaml.org/cache

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-> installed base-bigarray.base
-> installed base-threads.base
-> installed base-unix.base
[ERROR] The compilation of ocaml-system failed at "/root/.opam/opam-init/hooks/sandbox.sh build ocaml gen_ocaml_config.ml".

#=== ERROR while compiling ocaml-system.4.02.3 ================================#
# context     2.0.4 | linux/x86_64 |  | https://opam.ocaml.org#7f1f91d1f6bfe0200f8d27c1a92cb2138f5ff96f
# path        ~/.opam/default/.opam-switch/build/ocaml-system.4.02.3
# command     ~/.opam/opam-init/hooks/sandbox.sh build ocaml gen_ocaml_config.ml
# exit-code   1
# env-file    /tmp/opam-xxx-30/ocaml-system-30-562576.env
# output-file /tmp/opam-xxx-30/ocaml-system-30-562576.out
### output ###
# bwrap: Creating new namespace failed: Operation not permitted



<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
+- The following actions failed
| - build ocaml-system 4.02.3
+-
+- The following changes have been performed (the rest was aborted)
| - install base-bigarray base
| - install base-threads  base
| - install base-unix     base
+-
# Run eval $(opam env) to update the current shell environment
Switch initialisation failed: clean up? ('n' will leave the switch partially installed) [Y/n] y
root@pc1:~# uname -r
4.15.0-142-generic
root@pc1:~# 

[sebma]

Maybe it's a bubblewrap issue. So I created an issue on the bubblewrap project.

[sebma]

I solved my problem by disabling sandboxing in my opam call : opam init --disable-sandboxing -a

[punchagan]

See also this opam issue