Merge ~valentinviennot/ubuntu-docker-images:update-memcached-readme into ~ubuntu-docker-images/ubuntu-docker-images/+git/memcached:edge

[Valentin Viennot]

Extra parameters and additional debug docs (collapsible section).

[Sergio Durigan Junior (sergiodj)]

OK. I will address my comment about the network name in a subsequent commit.

review: Approve

diff --git a/README.md b/README.md
index b8a8027..dd5f31d 100644
--- a/README.md
+++ b/README.md
@@ -21,18 +21,20 @@ Read more on the [memcached website](https://memcached.org/).
 
 ```sh
 $ docker network create app-net --driver bridge
-$ docker run -d --name memcached --network app-net squeakywheel/memcached:edge
+$ docker run -d --name memcached --network app-net -e TZ=Europe/London squeakywheel/memcached:edge
 ```
 
 #### Parameters
 
 | Parameter | Description |
 |---|---|
-| `-e MEMCACHED_CACHE_SIZE=64MB` | Determines the size of the cache |
-| `-e MEMCACHED_MAX_CONNECTIONS=1024` | Determines the maximum number of concurrent connections |
-| `-e MEMCACHED_THREADS=4` | Determines the number of threads to process requests |
-| `-e MEMCACHED_PASSWORD` | Define the password for the `root` user if another username is provided. By default the authentication is disabled but if this option is passed it becomes enabled |
-| `-e MEMCACHED_USERNAME` | Define a new user. If this option is passed a password is needed to authenticate the new user |
+| `-e TZ=UTC` | Timezone. |
+| `-e MEMCACHED_CACHE_SIZE=64MB` | Determines the size of the cache. |
+| `-e MEMCACHED_MAX_CONNECTIONS=1024` | Determines the maximum number of concurrent connections. |
+| `-e MEMCACHED_THREADS=4` | Determines the number of threads to process requests. |
+| `-e MEMCACHED_PASSWORD` | Define the password for the `root` user if another username is provided. By default the authentication is disabled but if this option is passed it becomes enabled. |
+| `-e MEMCACHED_USERNAME` | Define a new user. If this option is passed a password is needed to authenticate the new user. |
+| `-p 11211` | Memcached is exposed inside the container on port `11211`. |
 
 #### Testing/Debugging
 
@@ -42,10 +44,32 @@ In case you need to debug what it is happening with the container you can run `d
 $ docker exec -it <name_of_the_container> /bin/bash
 ```
 
+<details>
+  <summary>You can access the memcached instance with telnet from another container (click to expand).</summary>
+
+```sh
+# Run an interactive container with the latest Ubuntu
+$ docker run -it --rm --name telnet --network app-net ubuntu bash
+# Install the telnet cli from within the container
+> apt update && apt install telnet -y
+# Connect to the memcached instance using telnet
+> telnet memcached 11211
+Trying 172.30.0.2...
+Connected to memcached.
+Escape character is '^]'.
+```
+From there you can run `memcached` commands, as documented in [their wiki](https://github.com/memcached/memcached/wiki/Commands).
+
+</details>
+
+```sh
+$ telnet memcached 11211
+```
+
 There are cases where one might want to pass some memcached command line flags that are not configurable via environment variables. In this case you can pass the flags themselves or a shell script:
 
 ```
-$ docker run -d --name memcached --network net squeakywheel/memcached:edge <flags_or_script_with_flags>
+$ docker run -d squeakywheel/memcached:edge <flags_or_script_with_flags>
 ```
 
 ### Deploy with Kubernetes
@@ -59,7 +83,6 @@ $ microk8s enable dns storage
 
 Use the sample deployment yaml provided [here](https://git.launchpad.net/~canonical-server/ubuntu-server-oci/+git/memcached/plain/examples/memcached-deployment.yml).
 
-
 <details>
   <summary>Apply the `memcached-deployment.yml` (click to expand)</summary>