Eddy Truyen created CASSANDRA-15717: ---------------------------------------
Summary: Benchmark performance difference between Docker and Kubernetes when running Cassandra:2.2.16 official Docker image Key: CASSANDRA-15717 URL: https://issues.apache.org/jira/browse/CASSANDRA-15717 Project: Cassandra Issue Type: Bug Components: Test/benchmark Reporter: Eddy Truyen Attachments: docker-cassandra-nodetool-tablestats, kube-adm-cassandra-nodetool-tablestats This is my first JIRA issue. Sorry if I do something wrong in the reporting. I experienced a performance degradation when running a single Cassandra Docker container inside Kubernetes in comparison with running the Docker container stand-alone. I used the following image decomads/cassandra:2.2.16, which uses cassandra:2.2.16 as base image and adds a readinessProbe to it. I used identical Docker configuration parameters by ensuring that the output of docker inspect is as much as possible the same. Docker runs in bridged mode Experiment (repeated on minikube+VirtualBox (12GB, 4 CPU cores, 30 GB) on physical laptop with 4 cores/8 logical processors and 16GB RAM on and Openstack VM Ubuntu 16:04 (4GB, 4 CPU cores, 50GB), that runs on a physical nodes with 16 CPU cores. Storage is Ceph. * A write-only workload (YCSB benchmark workload A - Load phase) using the following user table: cqlsh> create keyspace ycsb WITH REPLICATION = \{'class' : 'SimpleStrategy', 'replication_factor': 3 } ; cqlsh> USE ycsb; cqlsh> create table usertable ( y_id varchar primary key, field0 varchar, field1 varchar, field2 varchar, field3 varchar, field4 varchar, field5 varchar, field6 varchar, field7 varchar, field8 varchar, field9 varchar); * And using the following script: python ./bin/ycsb load cassandra2-cql -P workloads/workloada -p recordcount=1500000 -p operationcount=1500000 -p measurementtype=raw -p cassandra.connecttimeoutmillis=60000 -p cassandra.readtimeoutmillis=60000 -target 1500 -threads 20 -p hosts=localhost > results/cassandra-docker/cassandra-docker-load-workloada-1-records-1500000-rnd-1762034446.txt sleep 15 Observations: * Docker: ** Mean average response latency: 1500 ** Average CPU usage of cassandra instances (wrt 2 cores): 42 * Kubernetes ** Mean average response latency: 2700 ** Average CPU usage of cassandra instance (wrt 2 cores): 32% * Nodetool tablestats ** There are little difference for the usertable, with an almost identical write latency (difference < 0.002 ms). ** However for the system keyspace there are quite some differences in read/write count and read latency (difference = 2.5 ms). More specifically, compaction history (see attachment the 2 tablestats output) *** Table: compaction_history Kubernetes SSTable count: 1 Space used (live): 12049 Space used (total): 12049 Space used by snapshots (total): 0 Off heap memory used (total): 108 SSTable Compression Ratio: 0.25466231166368136 Number of keys (estimate): 54 Memtable data size: 0 Memtable off heap memory used: 0 Memtable switch count: 12 *** Table: compaction_history Docker SSTable count: 1 Space used (live): 8921 Space used (total): 8921 Space used by snapshots (total): 0 Off heap memory used (total): 76 SSTable Compression Ratio: 0.2603359822955437 Number of keys (estimate): 25 Memtable data size: 0 Memtable off heap memory used: 0 Memtable switch count: 1 * Cassandra Logs: * |Docker|Kubernetes| |ubuntu@k8-test-2:/data/ycsb/cassandra-docker$ grep -c 'Writing Memtable-compaction' docker-cassandra-logs 27 ubuntu@k8-test-2:/data/ycsb/cassandra-docker$ grep -c 'Writing Memtable-size' docker-cassandra-logs 1 ubuntu@k8-test-2:/data/ycsb/cassandra-docker$ grep -c ' Writing Memtable-sstable' docker-cassandra-logs 1 ubuntu@k8-test-2:/data/ycsb/cassandra-docker$ grep -c 'Writing Memtable-usertable' docker-cassandra-logs 45 ubuntu@k8-test-2:/data/ycsb/cassandra-docker$ grep -c 'Writing Memtable-compactions_in_progress' docker-cassandra-logs 26 ubuntu@k8-test-2:/data/ycsb/cassandra-docker$ grep -c 'Writing Memtable-peers' docker-cassandra-logs 1 ubuntu@k8-test-2:/data/ycsb/cassandra-docker$ grep -c 'Writing Memtable-schema' docker-cassandra-logs 24 ubuntu@k8-test-2:/data/ycsb/cassandra-docker$ grep -c 'Writing Memtable-local' docker-cassandra-logs 6|ubuntu@k8-test-2:/data/ycsb/cassandra-kube$ grep -c 'Writing Memtable-compaction' kubeadm-cassandra-logs \| more 32 ubuntu@k8-test-2:/data/ycsb/cassandra-kube$ grep -c 'Writing Memtable-size' kubeadm-cassandra-logs \| more 7 ubuntu@k8-test-2:/data/ycsb/cassandra-kube$ grep -c ' Writing Memtable-sstable' kubeadm-cassandra-logs \| more 7 ubuntu@k8-test-2:/data/ycsb/cassandra-kube$ grep -c 'Writing Memtable-usertable' kubeadm-cassandra-logs \| more 45 ubuntu@k8-test-2:/data/ycsb/cassandra-kube$ grep -c 'Writing Memtable-compactions_in_progress' kubeadm-cassandra-logs \| more 26 ubuntu@k8-test-2:/data/ycsb/cassandra-kube$ grep -c 'Writing Memtable-peers' kubeadm-cassandra-logs \| more 2 ubuntu@k8-test-2:/data/ycsb/cassandra-kube$ grep -c 'Writing Memtable-schema' kubeadm-cassandra-logs 17 ubuntu@k8-test-2:/data/ycsb/cassandra-kube$ grep -c 'Writing Memtable-local' kubeadm-cassandra-logs 5| Can the higher compaction rate of Kubernetes-based Cassandra instance be the cause of the latency for YCSB benchmark? 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