Calculate how long a docker pull will take given image size and network bandwidth.
Docker pull time depends on compressed image size, network bandwidth, and layer parallelism. Docker downloads up to 3 layers concurrently by default. Formula: pullTime ≈ compressedSize / (bandwidth/8) / min(parallelLayers, layerCount) + overhead.
Pull Time
pullTime = compressedSize / (bandwidth / 8) / parallelLayers + overhead
Registry rate limits, TLS handshake overhead, DNS resolution, layer decompression after download, and network congestion all add time beyond raw transfer speed.
Use a registry mirror close to your cluster, reduce image size with multi-stage builds and smaller base images, and increase --max-concurrent-downloads if bandwidth allows.