Not enough memory for Docker

We’re still on v10 and we’ve been getting so many issues like emails stopped being sent after we ran out of disk space, etc. I’m thinking of upgrading to the latest version v21 and so I did the following:

git pull

However I get this:
:arrow_forward: Defining variables and helpers …

:arrow_forward: Parsing command line …

:arrow_forward: Setting up error handling …

:arrow_forward: Checking minimum requirements …
FAIL: Required minimum RAM available to Docker is 3800 MB, found 3789 MB

How do I deal with this? I think our server is equipped with at least 8GB of memory. I’m trying to increase the memory allocated to the Docker sentry image but I honestly don’t know what I’m doing.

[root@ozeki onpremise]# docker images
REPOSITORY                             TAG                 IMAGE ID            CREATED             SIZE
sentry-cleanup-onpremise-local         latest              5126b9625432        10 months ago       789MB
sentry-onpremise-local                 latest              ee2ad78c5bef        10 months ago       787MB
getsentry/sentry                       latest              5aa0606524ba        10 months ago       787MB
<none>                                 <none>              440693e6bc78        10 months ago       789MB
getsentry/sentry                       <none>              d5478c03b815        10 months ago       787MB
snuba-cleanup-onpremise-local          latest              cb09a1254db4        10 months ago       476MB
symbolicator-cleanup-onpremise-local   latest              85d7b5af1ea0        10 months ago       158MB
<none>                                 <none>              5e637a4d8dc0        10 months ago       789MB
getsentry/symbolicator                 latest              215bfcae06c4        10 months ago       157MB
getsentry/sentry                       <none>              34cad9ceca72        10 months ago       787MB
getsentry/snuba                        latest              e0698e2bda8e        10 months ago       475MB
redis                                  5.0-alpine          5c5637d8a823        11 months ago       29.8MB
alpine                                 latest              a187dde48cd2        11 months ago       5.6MB
busybox                                latest              83aa35aa1c79        11 months ago       1.22MB
postgres                               9.6                 16f0ba6ed857        11 months ago       200MB
tianon/exim4                           latest              4d6326f71602        11 months ago       176MB
memcached                              1.5-alpine          0dbf6b4c454b        12 months ago       9.19MB
yandex/clickhouse-server               19.11               0d4181b5021f        14 months ago       482MB
confluentinc/cp-kafka                  5.1.2               163b44d95ebe        23 months ago       571MB
confluentinc/cp-zookeeper              5.1.2               5d4b53b82897        23 months ago       571MB
hello-world                            latest              fce289e99eb9        2 years ago         1.84kB
[root@ozeki onpremise]# docker run -it --memory="4g" getsentry/sentry
!! Configuration error: Exception: Error: REDIS_PORT_6379_TCP_ADDR (or SENTRY_REDIS_HOST) is undefined, did you forget to `--link` a redis container?