SNMP migration from snmp.yml to ConfigDB

doc/snmp/snmp-configdb-migration-hld.md

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+# SNMP Migration from snmp.yml to ConfigDB
+# High Level Design Document
+### Rev 0.1
+
+###### Revision
+| Rev |     Date    |       Author       | Change Description                |
+|:---:|:-----------:|:------------------:|-----------------------------------|
+| 0.1 |             | Travis Van Duyn    | Initial version                   |
+
+# About this Manual
+This document provides general information about the migration of SNMP community information from snmp.yml file to the ConfigDB.
+# Scope
+Currently we are using the /etc/sonic/snmp.yml file to populate the SNMP communities in the /etc/snmp/snmpd.conf file.
+The goal of this update is to move away from the snmp.yml file and move towards the ConfigDB for better supportibility and ease of use.
+
+
+# Config DB
+## SNMP SCHEMA
+Some new "SNMP" tables should be added to ConfigDB in order to store SNMP related configuration.
+https://github.com/Azure/SONiC/blob/master/doc/snmp/snmp-schema-addition.md
+
+The new SNMP tables are:
+SNMP
+SNMP_COMMUNITY
+SNMP_USER
+
+
+# SNMP Table
+```
+SNMP|LOCATION
+SNMP|CONTACT
+
+admin@switch1:~$ redis-cli -n 4 hgetall "SNMP|LOCATION"
+1) "LOCATION"
+2) "Emerald City"
+
+admin@switch1:~$ redis-cli -n 4 hgetall "SNMP|CONTACT"
+1) "joe"
+2) "joe@contoso.com"
+```
+
+# SNMP_COMMUNITY Table
+```
+SNMP_COMMUNITY|<community>
+
+admin@switch1:~$ redis-cli -n 4 hgetall "SNMP_COMMUNITY|Jack"
+1) "TYPE"
+2) "RW"
+
+```
+
+# SNMP_USER Table
+```
+SNMP_USER|<user>
+
+admin@switch1:~$ redis-cli -n 4 hgetall "SNMP_USER|Travis"
+ 1) "SNMP_USER_ENCRYPTION_TYPE"
+ 2) "AES"
+ 3) "SNMP_USER_AUTH_TYPE"
+ 4) "SHA"
+ 5) "SNMP_USER_ENCRYPTION_PASSWORD"
+ 6) "TravisEncryptPass"
+ 7) "SNMP_USER_AUTH_PASSWORD"
+ 8) "TravisAuthPass"
+ 9) "SNMP_USER_TYPE"
+10) "Priv"
+11) "SNMP_USER_PERMISSION"
+12) "RO"
+```
+
+
+
+# New SNMP CLI Commands
+# Show commands
+```
+admin@switch1:~$ show run snmp -h
+Usage: show run snmp [OPTIONS] COMMAND [ARGS]...
+
+  Show SNMP running configuration
+
+Options:
+  -?, -h, --help  Show this message and exit.
+
+Commands:
+  community  show running configuration snmp community
+  contact    show running configuration snmp contact
+  location   show running configuration snmp location
+  users      show running configuration snmp users
+admin@switch1:~$
+```
+
+show run snmp community
+```
+admin@switch1:~$ show run snmp community
+Community String    Community Type
+------------------  ----------------
+Qi                  RO
+Travis              RO
+Bill                RO
+Jack                RW
+public              RO
+Joker               RW
+admin@switch1:~$
+```
+
+show run snmp contact
+```
+admin@switch1:~$ show run snmp contact
+Contact    Contact Email
+---------  -----------------
+Joe        joe@contoso.com
+admin@switch1:~$
+```
+
+show run snmp location
+```
+admin@switch1:~$ show run snmp location
+Location
+----------
+Redmond
+admin@switch1:~$
+```
+
+show run snmp users
+```
+admin@switch1:~$ show run snmp users
+User    Type    Auth Type    Auth Password    Encryption Type    Encryption Password
+------  ------  -----------  ---------------  -----------------  ---------------------
+Travis  Priv    SHA          TravisAuthPass   AES                TravisEncryptPass
+admin@switch1:~$
+```
+
+
+# Config Commands
+```
+admin@switch1:~$ sudo config snmp -h
+Usage: config snmp [OPTIONS] COMMAND [ARGS]...
+
+  SNMP configuration tasks
+
+Options:
+  -?, -h, --help  Show this message and exit.
+
+Commands:
+  community
+  contact
+  location
+  user
+admin@switch1:~$
+```
+
+sudo config snmp community
+```
+admin@switch1:~$ sudo config snmp community -h
+Usage: config snmp community [OPTIONS] COMMAND [ARGS]...
+
+Options:
+  -?, -h, --help  Show this message and exit.
+
+Commands:
+  add  Add snmp community
+  del  Delete snmp community
+admin@switch1:~$
+admin@switch1:~$ sudo config snmp community add -h
+Usage: config snmp community add [OPTIONS] <snmp_community> <RO|RW>
+
+  Add snmp community
+
+Options:
+  -?, -h, --help  Show this message and exit.
+admin@switch1:~$ 
+admin@switch1:~$ 
+admin@switch1:~$ sudo config snmp community del -h
+Usage: config snmp community del [OPTIONS] <snmp_community>
+
+  Delete snmp community
+
+Options:
+  -?, -h, --help  Show this message and exit.
+admin@switch1:~$
+
+
+admin@switch1:~$ sudo config snmp community -h
+Usage: config snmp community [OPTIONS] COMMAND [ARGS]...
+
+Options:
+  -?, -h, --help  Show this message and exit.
+
+Commands:
+  add      Add snmp community string
+  del      Delete snmp community string
+  replace  Replace snmp community string
+admin@switch1:~$ sudo config snmp community replace -h
+Usage: config snmp community replace [OPTIONS] <current_community_string>
+                                     <new_community_string>
+
+  Replace snmp community string
+
+Options:
+  -?, -h, --help  Show this message and exit.
+admin@switch1:~$ 
+```
+
+sudo config snmp contact
+```
+admin@switch1:~$ sudo config snmp contact -h
+Usage: config snmp contact [OPTIONS] COMMAND [ARGS]...
+
+Options:
+  -?, -h, --help  Show this message and exit.
+
+Commands:
+  modify  Modify snmp contact
+admin@switch1:~$
+```
+
+sudo config snmp location
+```
+admin@switch1:~$ sudo config snmp location -h
+Usage: config snmp location [OPTIONS] COMMAND [ARGS]...
+
+Options:
+  -?, -h, --help  Show this message and exit.
+
+Commands:
+  modify  Modify snmp location
+admin@switch1:~$
+```
+
+sudo config snmp user
+```
+admin@switch1:~$ sudo config snmp user -h
+Usage: config snmp user [OPTIONS] COMMAND [ARGS]...
+
+Options:
+  -?, -h, --help  Show this message and exit.
+
+Commands:
+  add  Add snmp user
+  del  Delete snmp user
+admin@switch1:~$
+admin@switch1:~$ sudo config snmp user add -h
+Usage: config snmp user add [OPTIONS] <snmp_user>
+                            <noAuthNoPriv|AuthNoPriv|Priv> <RO|RW> <MD5|SHA
+                            |HMAC-SHA-2> <auth_password> <DES|AES>
+                            <encrypt_password>
+
+  Add snmp user
+
+Options:
+  -?, -h, --help  Show this message and exit.
+admin@switch1:~$ sudo config snmp user del -h
+Usage: config snmp user del [OPTIONS] <snmp_user>
+
+  Delete snmp user
+
+Options:
+  -?, -h, --help  Show this message and exit.
+admin@switch1:~$ 
+```
+
+# Migration Plan
+In order to move from using the snmp.yml file to using the Redis ConfigDB here are the things the need to be done to move this in a way that is backward compatible.
+1. Create a python conversion script to parse the data in snmp.yml file and store it in ConfigDB using the above schema.
+2. Update Dockerfile.j2 in docker-snmp container to add a line to copy over new python conversion script to "/usr/bin/"
+3. Update the snmpd.conf.j2 jinja template to pull SNMP information from only the Redis ConfigDB
+4. Update start.sh in docker-snmp container as follows:
+    - Add a line above the `sonic-cfggen` call to run the python conversion script from step 1 (which will run every time this docker container starts)
+    - Remove the `-y /etc/sonic/snmp.yml` argument from the existing call to sonic-cfggen as it will no longer needed because the python conversion script above will have already loaded that data into Config DB
+
+
+# Notes:
+A new docker-snmp container with all the above updates will be created so that we will eventually be able to remove the snmp.yml file and only use the Redis ConfigDB after we socalize the update.
+
+If we do the migration in this way then when we rollout a new docker-snmp container to the existing devices we will still support the information in the snmp.yml file but we'll also be able to get the information from the Redis ConfigDB for all the new show and config commands.