Before you begin reading this guide, we recommend you try running the Elasticsearch Error Check-Up which can resolve issues that cause many errors.
This guide will help you check for common problems that cause the log ” command missing the node parameter ” to appear. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: routing, node, allocation and cluster.
Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up which analyses ES to pinpoint the cause of many errors and provides suitable actionable recommendations how to resolve them (free tool that requires no installation).
Overview
In Elasticsearch, routing refers to document routing. When you index a document, Elasticsearch will determine which shard will be used to index the document to.
The shard is selected based on the following formula:
shard = hash(_routing) % number_of_primary_shards
Where the default value of _routing is _id.
It is important to know which shard the document is routed to, because Elasticsearch will need to determine where to find that document later on for document retrieval requests.
Examples
In twitter index with 2 primary shards, the document with _id equal to “440” gets routed to the shard number:
shard = hash( 440 ) % 2
PUT twitter/_doc/440
{
...
}
Notes and good things to know
- In order to improve search performance speed you can create custom routing. For example, you can enable custom routing that will ensure only a single shard is queried (the shard that contains your data).
- To create custom routing in Elasticsearch, you will need to configure and define that not all routing will be completed by default settings. ( v <= 5.0)
PUT my_index/customer/_mapping
{
"order":{
"_routing":{
"required":true
}
}
}- This will ensure that every document in the “customer” type must specify a custom routing. For elasticsearch 6 or above you will need to update the same mapping as:
PUT my_index/_mapping
{
"order":{
"_routing":{
"required":true
}
}
}Overview
Simply put a node is a single server that is part of a cluster. Each node is assigned one or more roles, which describe the node’s responsibility and operations – Data nodes stores the data, and participates in the cluster’s indexing and search capabilities, while master nodes are responsible for managing the cluster’s activities and storing the cluster state, including the metadata.
While it is possible to run several node instances of Elasticsearch on the same hardware, it’s considered a best practice to limit a server to a single running instance of Elasticsearch.
Nodes connect to each other and form a cluster by using a discovery method.
Roles
Master node
Master nodes are in charge of cluster-wide settings and changes – deleting or creating indices and fields, adding or removing nodes and allocating shards to nodes. Each cluster has a single master node that is elected from the master eligible nodes using a distributed consensus algorithm and is reelected if the current master node fails.
Coordinator or client node
Coordinator Nodes are nodes that do not hold any configured role. They don’t hold data, are not part of the master eligible group nor execute ingest pipelines. Coordinator nodes serve incoming search requests and act as the query coordinator running query and fetch phases, send requests to every node that holds a shard being queried. The client node also distributes bulk indexing operations and route queries to shards based on the node’s responsiveness.
Log Context
Log”[{}] command missing the node parameter”classname is CancelAllocationCommand.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :
}
if (shardId == -1) {
throw new ElasticsearchParseException("[{}] command missing the shard parameter"; NAME);
}
if (nodeId == null) {
throw new ElasticsearchParseException("[{}] command missing the node parameter"; NAME);
}
return new CancelAllocationCommand(index; shardId; nodeId; allowPrimary);
}
@Override