Fix some errors in the upgrade guide to 1.5.0 and add some missing notes discovered by users. (#2160)

docs/operations/upgrade.md

@@ -52,13 +52,13 @@ This may affect people in a couple ways:
 
 #### Loki Port
 
-If you are running Loki with a config that opens a port number above 1000 (which is the default, 3100 for HTTP and 9095 for GRPC) everything should work fine in regards to ports.
+If you are running Loki with a config that opens a port number above 1024 (which is the default, 3100 for HTTP and 9095 for GRPC) everything should work fine in regards to ports.
 
-If you are running Loki with a config that opens a port number less than 1000 Linux normally requires root permissions to do this, HOWEVER in the Docker container we run `setcap cap_net_bind_service=+ep /usr/bin/loki`
+If you are running Loki with a config that opens a port number less than 1024 Linux normally requires root permissions to do this, HOWEVER in the Docker container we run `setcap cap_net_bind_service=+ep /usr/bin/loki`
 
-This capability lets the loki process bind to a port less than 1000 when run as a non root user.
+This capability lets the loki process bind to a port less than 1024 when run as a non root user.
 
-Not every environment will allow this capability however, it's possible to restrict this capability in linux.  If this restriction is in place, you will be forced to run Loki with a config that has HTTP and GRPC ports above 1000.
+Not every environment will allow this capability however, it's possible to restrict this capability in linux.  If this restriction is in place, you will be forced to run Loki with a config that has HTTP and GRPC ports above 1024.
 
 #### Filesystem
 
@@ -106,6 +106,49 @@ The intermediate step of using an ubuntu image to change the ownership of the Lo
 That is if you have access to `/var/lib/docker/volumes` or if you mounted to a different local filesystem directory, you can change the ownership directly without using a container. 
 
 
+### Loki Duration Configs
+
+If you get an error like:
+
+```nohighlight
+ ./loki-linux-amd64-1.5.0 -log.level=debug -config.file=/etc/loki/config.yml
+failed parsing config: /etc/loki/config.yml: not a valid duration string: "0"
+```
+
+This is because of some underlying changes that no longer allow durations without a unit.
+
+Unfortunately the yaml parser doesn't give a line number but it's likely to be one of these two:
+
+```yaml
+chunk_store_config:
+  max_look_back_period: 0s # DURATION VALUES MUST HAVE A UNIT EVEN IF THEY ARE ZERO
+
+table_manager:
+  retention_deletes_enabled: false
+  retention_period: 0s # DURATION VALUES MUST HAVE A UNIT EVEN IF THEY ARE ZERO
+```
+
+### Promtail Config Changes
+
+The underlying backoff library used in promtail had a config change which wasn't originally noted in the release notes:
+
+If you get this error:
+
+```nohighlight
+Unable to parse config: /etc/promtail/promtail.yaml: yaml: unmarshal errors:
+  line 3: field maxbackoff not found in type util.BackoffConfig
+  line 4: field maxretries not found in type util.BackoffConfig
+  line 5: field minbackoff not found in type util.BackoffConfig
+```
+
+The new values are:
+
+```yaml
+min_period:
+max_period:
+max_retries: 
+```
+
 ## 1.4.0
 
 Loki 1.4.0 vendors Cortex v0.7.0-rc.0 which contains [several breaking config changes](https://github.com/cortexproject/cortex/blob/v0.7.0-rc.0/CHANGELOG.md).