Activate gzip compression on the Istio-proxy workload

2 min readMay 2, 2021

Do you want to optimize your network bandwidth easy way?
Envoy compression filter helps us to improve this process.

Istio doesn't have any CRD to enable gzip compression. Alright at this point EnvoyFilter rescues us to enable gzip.

Gzip is an HTTP filter that enables Envoy to compress dispatched data from an upstream service upon client request. Compression is useful in situations where large payloads need to be transmitted without compromising the response time.

Before Istio 1.7

Enable gzip any workload or istio-ingress gw

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: application-gzip
  namespace: istio-system
spec:
  workloadSelector:
    labels:
      app: workload-app
  configPatches:
    - applyTo: HTTP_FILTER
      match:
        context: SIDECAR_INBOUND
        listener:
          filterChain:
            filter:
              name: "envoy.http_connection_manager"
              subFilter:
                name: 'envoy.router'
      patch:
        operation: INSERT_BEFORE
        value:
          name: envoy.gzip
          config:
            remove_accept_encoding_header: true
            compression_level: DEFAULT
            compression_strategy:

How it works

When gzip filter is enabled, request and response headers are inspected to determine whether or not the content should be compressed.

config.filter.http.gzip.v2.Gzip

memory_level: 1 to 9
Value from 1 to 9 that controls the amount of internal memory used by zlib.compression_level: DEFAULT|BEST|SPEED
A value used for selecting the zlib compression level.compression_strategy: DEFAULT|FILTERED|HUFFMAN|RLE
A value used for selecting the zlib compression strategy which is directly related to the characteristics of the content.

config.filter.http.compressor.v2.Compressor

content_length: Minimum response length, in bytes, which will trigger compressioncontent_type:  Set of strings that allows specifying which mime-types yield compression

After Istio 1.7

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: application-gzip
  namespace: istio-system
spec:
  workloadSelector:
    labels:
      app: workload-app
  configPatches:
    - applyTo: HTTP_FILTER
      match:
        context: SIDECAR_INBOUND
        listener:
          filterChain:
            filter:
              name: envoy.http_connection_manager
              subFilter:
                name: envoy.router
      patch:
        operation: INSERT_BEFORE
        value:
          name: envoy.filters.http.compressor
          typed_config:
            '@type': type.googleapis.com/envoy.extensions.filters.http.compressor.v3.Compressor
            compressor_library:
              name: text_optimized
              typed_config:
                '@type': type.googleapis.com/envoy.extensions.compression.gzip.compressor.v3.Gzip
            remove_accept_encoding_header: true

Statistics

Every configured Compressor filter has statistics rooted at <stat_prefix>.compressor.<compressor_library.name>.<compressor_library_stat_prefix>.<direction_prefix>.* with the following: