How to set the tls part in the filebeat.yml....alway wrong

Elastic Stack Beats
3

realy realy thank
my filebeat version is 1.3.1 logstash version is 2.4
I don't know how many times I have tried having a self-signed server certificate, I always get a error:
Looks like you either have an invalid key or your private key was not in PKCS8 format. {:exception=>java.lang.IllegalArgumentException: File does not contain valid private key: /etc/server/key/server.key, :level=>:error}

this is my command in order:
1.get a CA
1.1 openssl genrsa -out ca.key 2048
1.2 openssl req -new -x509 -days 3650 -key ca.key -out ca.crt -subj "/C=CN/ST=guangdong/L=shenzhen/O=litianbl/OU=gamecenter"
1.3.1 mkdir demoCA
. . .2 cd demoCA/
.....3 mkdir newcerts
......4 touch index.txt
......5 echo 01 > serial
2. get server's certificates
2.0 cd ..
2.1 openssl genrsa -out server.key 2048
2.2 openssl req -new -key server.key -out server.csr -subj "/C=CN/ST=guangdong/L=shenzhen/O=litianbl/OU=gamecenter/CN=192.168.147.128"
2.3 openssl ca -in server.csr -out server.crt -cert ca.crt -keyfile ca.key
2.4 openssl verify -CAfile ca.crt server.crt
the console output after this command is: server.crt: OK
3.get client's certificates
3.1 openssl genrsa -out client.key 2048
3.2 openssl req -new -key client.key -out client.csr -subj "/C=CN/ST=guangdong/L=shenzhen/O=litianbl/OU=gamecenter/CN=192.168.147.129"
3.3 openssl ca -in client.csr -out client.crt -cert ca.crt -keyfile ca.key
3.4 openssl verify -CAfile ca.crt client.crt
after this command ,the console output: client.crt: OK
4. test
4.1 open a terminal 1 and then :
openssl s_server -accept 10001 -key server.key -cert server.crt 4.2 open a terminal 2 and then: openssl s_client -connect localhost:10001
I can get what I input in terminal 2 from terminal 1.and in another way I also can get what i input in terminal 1 from terminal 2.

so, I think these certificates are ok. and the I reconfigured the logstash.conf and filebeat.yml :

and finaly I still get this........

could you help me with this ..........please :sob::sob::sob: cos I have searched this error on the internet,but nothing I got.
somebody help ......