Adding docs on UF sidecar model

[nwang92]

Adding some docs to address #186

[nwang92]

Build errors related to some RedHat change :(

Step 1/5 : FROM registry.access.redhat.com/ubi8/ubi-minimal
latest: Pulling from ubi8/ubi-minimal


Digest: sha256:7b7a9336b681f779b239141db4fd27fed9a7cc50e7ef7a727fc9490559b4e1df
Status: Downloaded newer image for registry.access.redhat.com/ubi8/ubi-minimal:latest
 ---> 3bfa511b67f8
Step 2/5 : LABEL maintainer "support@splunk.com"
 ---> Running in 31117d07e534
 ---> 183639f145b3
Removing intermediate container 31117d07e534
Step 3/5 : COPY install.sh /install.sh
 ---> a16c236c0d64
Step 4/5 : COPY EULA_Red_Hat_Universal_Base_Image_English_20190422.pdf /EULA_Red_Hat_Universal_Base_Image_English_20190422.pdf
 ---> 20163c1f569f
Step 5/5 : RUN /install.sh && rm -rf /install.sh
 ---> Running in fcec834e844b

(process:6): librhsm-WARNING **: 00:12:56.912: Found 0 entitlement certificates

(process:6): librhsm-WARNING **: 00:12:56.915: Found 0 entitlement certificates
Downloading metadata...
Downloading metadata...
error: cannot update repo 'ubi-8-appstream': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried; Last error: Curl error (28): Timeout was reached for https://cdn-ubi.redhat.com/content/public/ubi/dist/ubi8/8/x86_64/appstream/os/repodata/repomd.xml [Operation timed out after 30001 milliseconds with 0 out of 0 bytes received]

[blackumbrella]

Hey experts

After reading the example document, I still have one question: in splunk UF example, we need to provide below env:

• name: SPLUNK_USER
  value: root
  • name: SPLUNK_GROUP
    value: root
  • name: SPLUNK_PASSWORD
    value: helloworld

but shall we define this user, password and group in the splunk enterprise first? The document didn't mention this process.