Upgrade Loki

Prerequisites

FROM_LOKI_VERSION=xxx
TO_LOKI_VERSION=xxx

List of changes

Several steps :

• identify the main changes with the release-notes
• read the full changelog
• identify the upgrade impacts
• identify configuration differences between both versions

  cd /tmp
  export CONFIG_FILE=local-config.yaml
  
  docker run --rm -t grafana/loki:${FROM_LOKI_VERSION} -config.file=/etc/loki/${CONFIG_FILE} -print-config-stderr 2>&1 | sed '/Starting Loki/q' > /tmp/loki_${FROM_LOKI_VERSION}
  docker run --rm -t grafana/loki:${TO_LOKI_VERSION} -config.file=/etc/loki/${CONFIG_FILE} -print-config-stderr 2>&1 | sed '/Starting Loki/q' > /tmp/loki_${TO_LOKI_VERSION}
  
  # Edit both files in /tmp and remove the first and last lines that are not configurations
  vim /tmp/loki_${FROM_LOKI_VERSION}
  vim /tmp/loki_${TO_LOKI_VERSION}
  
  cat /tmp/loki_${FROM_LOKI_VERSION} | yq -S . > /tmp/loki_${FROM_LOKI_VERSION}_sort
  cat /tmp/loki_${TO_LOKI_VERSION} | yq -S . > /tmp/loki_${TO_LOKI_VERSION}_sort
  
  diff --color=always --side-by-side /tmp/loki_${FROM_LOKI_VERSION}_sort /tmp/loki_${TO_LOKI_VERSION}_sort
  

Testing the configuration file with new version

Prerequisites

Retrieve the configuration file into a file

kubectl -n "${NAMESPACE}" get configmap loki -o jsonpath="{.data.config\.yaml}" > /tmp/loki.config.yaml

Test the configuration file

cd /tmp
docker run --rm -t -v "$(pwd)":/config grafana/loki:${TO_LOKI_VERSION} -config.file=/config/loki.config.yaml -verify-config=true

Expected result :

level=info ... msg="config is valid"

Example of error :

failed parsing config: /config/loki.config.yaml: yaml: unmarshal errors:
  line 27: field shared_store not found in type compactor.Config