Merge ~cjwatson/launchpad-mojo-specs:git-bump-maxconn into launchpad-mojo-specs:master

[Colin Watson]

git: Bump haproxy net.core.somaxconn

`net.core.somaxconn 4096` is the default as of Linux 5.4, but the haproxies here are still on bionic and thus Linux 4.15.

[Simone Pelosi (pelpsi)]

LGTM!

review: Approve

[Guruprasad (lgp171188)]

https://code.launchpad.net/~hloeung/launchpad-mojo-specs/+git/launchpad-mojo-specs/+merge/453096 adds a higher value for `maxconn` and this change has already been deployed manually by Haw (on William's advice) to fix the haproxy issue.

[Colin Watson (cjwatson)]

I've landed Haw's changes and rebased this against them - there are still a few things left as cowboys on production, so I'll land this to resolve those.

diff --git a/lp-git/bundle.yaml b/lp-git/bundle.yaml
index a4e9f89..36a9aab 100644
--- a/lp-git/bundle.yaml
+++ b/lp-git/bundle.yaml
@@ -184,7 +184,9 @@ applications:
       ssl_key: ""
 {%- endif %}
       sysctl: |
+        net.core.somaxconn: 4096
         net.ipv4.tcp_congestion_control: bbr
+        net.ipv4.tcp_max_syn_backlog: 2048
 {%- if not devel %}
   autocert-haproxy:
     charm: cs:~autocert-charmers/autocert-17