https://issues.apache.org/jira/browse/CLOUDSTACK-3471
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As of cloudstack 4.3 there is no api that can aggregate log messages by the job id. Since logging is a typically a service that can be and is usually available outside the IaaS core, it was felt that instead of integrating this as an api within cloudstack, it would be better to provide a generic logsearch service that could be invoked by cloudstack to retrieve log messages. We describe the mechanism on how to achieve this in what follows.
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This is typically useful to root admin users.
Author | Description | Date |
---|---|---|
Saurav Lahiri | Inital Draft | 12/14/2013 |
Saurav Lahiri | Changes to describe how the service will be deployed and used | 2/11/2013 |
Root Admin users can query this service to quickly identify the sequence of steps related to a particular Job.
QA can use this service to link the log messages related to automated test failures.
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The system will comprise of a log shipping layer. This layer will be responsible for collecting logs from each of the management server shipping them to a centralized place. We describe how logstash can be used as the shipping layer. It will be configured to use redis to ship individual log files to a centralized location. Fluentd could be another option.
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Elasticsearch runs as a horizontal scale out cluster. The clusters node can be created in two different modes.
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We describe the process of creating and using seperate Elastic search nodes:
In this configuration any linux user template can be used to spawn elasticsearch nodes. The number of such nodes should
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be configurable via a global parameter. One of the
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node will be designated as the master node, which will also run the
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redis instance.
Using systemvm for elasticsearch nodes:
Currently cloudstack does not allow deployment of default system vms. The only supported types are (virtual router, secondary storage, consoleproxy, internal and external load balancer). These specifc types are handle in their specific Manager code. To enable systemvms to be started by admin, Default System VM manager and VO class will require to be implemented.
Logstash Configuration on the log shipping layer.
Code Block |
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input { |
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file |
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{ type => "apache" |
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path => [ "/var/log/cloudstack/management/management-server.log" ] |
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} } output { stdout { codec => rubydebug } redis { host => "192.168.56.100" data_type => "list" key => "logstash" } } |
Logstash configuration on the index/search layer.
Code Block |
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input |
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{ redis { host => "<host>" # these settings should match the output of the agent data_type => "list" key => "logstash" # We use the 'json' codec here because we expect to read # json events from redis. codec => json } } filter { grok { match => [ "message","%{YEAR:year}-%{MONTHNUM:month}-%{MONTHDAY}[T ]%{HOUR} |
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:?%{MINUTE} |
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:?%{SECOND}[T ]INFO%{GREEDYDATA}job[\-]+%{INT |
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:jobid}\s*=\s*\[\s*%{UUID |
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:uuid}\s* |
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\]%{GREEDYDATA}" |
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]
named_captures_only => true
}
}
output
{
stdout { debug => true debug_format => "json"}
elasticsearch {
}
}
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This will help configuring unicast discovery of master nodes. Multicast discovery can also be used but is not described here. By default all nodes are enabled to function as master. The actual master is elected through a elasticsearch master election process.
On each elasticsearch node:
discovery.zen.ping.unicast.hosts: ["host1", "host2"]
network.publish_host: host1
The following two scripts can automate steps 1 to 5 for the above process.
This script takes all the paramters in a setup config file. The only line param this requires is the config file. Default setup.conf is adequately commented
to describe the required params.
~# ./setup_es_template.sh --config setup.conf
#########################################################################################################
#This is the base template which will be used to provision a guest with logstash,elasticsearch and redis
templateid=
#The diskoffering fo the guest
diskofferingid=
#The serviceofferingid
serviceofferingid=
#The zoneid
zoneid=
#Currently only linux, dont change this
ostype=linux
#The default is to use the username/pass, fill this up if the ssh keyfile will be used
keyfile=""
#Username with which the various steps will be carried out
user=root
#Default is to use the password to automate the provisioning into the vm
passwd=
#The yum repo url for logstash
logstash_baseurl="http://packages.elasticsearch.org/logstash/1.3"
#Description for logstash software
logstash_desc="logstash repository for 1.3.x packages"
#Gpg key for the logstash repo
logstash_gpgkey="http://packages.elasticsearch.org/GPG-KEY-elasticsearch"
#Logstash reponame
logstash_reponame="\[logstash-1.3\]"
#The conf file which will be used to specify the cloudstack specfic config info
logstash_conf=./logstash-indexer.conf
#The yum repo url for elasticsearch
elasticsearch_baseurl="http://packages.elasticsearch.org/elasticsearch/0.90/centos"
#Description for elasticsearch software
elasticsearch_desc="Elasticsearch repository for 0.90.x packages"
#The gpg key for repo
elasticsearch_gpgkey="http://packages.elasticsearch.org/GPG-KEY-elasticsearch"
#The elasticsearch reponame
elasticsearch_reponame="\[elasticsearch-0.90\]"
#The epel repo rpm
epelrpm=http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
#The remi repo rpm
remirpm=http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
#########################################################################################################
output {
elasticsearch {
host => "<elasticsearch_master>"
}
}
A new API command ExtractLogByJobIdCmd will be introduced. This will be implemented as a synchronous command.
The manager class will implement the actual functionality of querying elastic search for log messages that match the specified filters. For doing this the Elasticsearch REST api queries will be used. Post method will be used with elasticsearch DSL to specify the required query. DSL is quite flexible and in future if support is required to filter by time stamp and other values DSL would help achieve that with ease.
DSL query for searching logs by jobid
{
"query": {
"query_string": {
"query": "\<jobid\>",
"fields" : "jobid"
}
}
}
A new API will introduced which can be accessed as
http://<host>:8080/client/api?command=extractLogByJobId&jobid=<jobid>
Code Block |
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import org.apache.commons.httpclient.HttpStatus;
import org.apache.http.entity.StringEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.HttpResponse;
import org.apache.http.impl.client.DefaultHttpClient;
import java.io.*;
class SampleSearch
{
public static void main(String []args)
{
try{
DefaultHttpClient httpClient = new DefaultHttpClient();
String url = "http://192.168.56.100:9200/_search" ;
StringEntity data = new StringEntity("{ \"query\": { \"query_string\": { \"query\": \"2005\", \"fields\" : [\"jobid\"] } } }");
HttpPost request = new HttpPost(url);
request.addHeader("content-type", "application/x-www-form-urlencoded");
request.setEntity(data);
HttpResponse response = httpClient.execute(request);
if(response.toString().contains("200 OK"))
{
InputStream is = response.getEntity().getContent();
BufferedReader in = new BufferedReader(new InputStreamReader(is));
String line = null;
StringBuilder responseData = new StringBuilder();
while((line = in.readLine()) != null)
{
responseData.append(line);
}
System.out.println("RESPONSE : " + responseData.toString());
}
}
catch(Exception exp)
{
System.out.println("Error ocurred:" + exp.toString());
}
}
}
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