Category: Linux

Juhtusin biker.ee foorumis lugema arutelu mootori võimsuse üle ja Randeli seletus meeldis niivõrd, et peab endale kohe ülesse kirjutama. Tsitaadi algus:

Et maakeeles võimsuse ja pöördemomendi vahe selgeks teha, kujutlege järgmist olukorda:
On vaja tassida 100 tellist punktist A punkti B
Üks tööline tassib 10 kivi korraga (suur pöördemoment) ja teine 2 kivi korraga (väike pöördemoment)
Esimene tööline käib aeglaselt (madalad pöörded) ja teeb töö ära näiteks 1 tunniga.
Teine lidub kiirelt (kõrged pöörded) ja saab 45 minutiga hakkama.
See kumb saab töö kiiremini tehtud, ongi võimsam.
Mootoriga on täpselt sama loogika.

Tsitaadi lõpp.

https://www.certmetrics.com/amazon/public/badge.aspx?i=1&t=c&d=2020-01-07&ci=AWS00990783

Wanted to test Centos 8 so created docker image to test it.

This is my Dockerfile

FROM centos:latest
RUN yum -y install httpd; yum clean all; systemctl enable httpd.service
EXPOSE 80
CMD ["/usr/sbin/init"]

Build image

docker build --rm -t local/c8-systemd-httpd .

mintty screen dump

$ nslookup.exe -type=SOA -debug roo.ee                                                                                                                                                                                                                                         
Non-authoritative answer:                                                                                                                                                                                                                                                      
------------                                                                                                                                                                                                                                                                   
Got answer:                                                                                                                                                                                                                                                                    
    HEADER:                                                                                                                                                                                                                                                                    
        opcode = QUERY, id = 1, rcode = NXDOMAIN                                                                                                                                                                                                                               
        header flags:  response, want recursion, recursion avail.                                                                                                                                                                                                              
        questions = 1,  answers = 0,  authority records = 1,  additional = 0                                                                                                                                                                                                   
                                                                                                                                                                                                                                                                               
    QUESTIONS:                                                                                                                                                                                                                                                                 
        8.49.98.192.in-addr.arpa, type = PTR, class = IN                                                                                                                                                                                                                       
    AUTHORITY RECORDS:                                                                                                                                                                                                                                                         
    ->  98.192.in-addr.arpa                                                                                                                                                                                                                                                    
        ttl = 2797 (46 mins 37 secs)                                                                                                                                                                                                                                           
        primary name server = sjoki.uta.fi                                                                                                                                                                                                                                     
        responsible mail addr = vg.sjoki.uta.fi                                                                                                                                                                                                                                
        serial  = 2019030709                                                                                                                                                                                                                                                   
        refresh = 28800 (8 hours)                                                                                                                                                                                                                                              
        retry   = 7200 (2 hours)                                                                                                                                                                                                                                               
        expire  = 1209600 (14 days)                                                                                                                                                                                                                                            
        default TTL = 86400 (1 day)                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                               
------------                                                                                                                                                                                                                                                                   
Server:  UnKnown                                                                                                                                                                                                                                                               
Address:  192.98.49.8                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                               
------------                                                                                                                                                                                                                                                                   
Got answer:                                                                                                                                                                                                                                                                    
    HEADER:                                                                                                                                                                                                                                                                    
        opcode = QUERY, id = 2, rcode = NOERROR                                                                                                                                                                                                                                
        header flags:  response, want recursion, recursion avail.                                                                                                                                                                                                              
        questions = 1,  answers = 1,  authority records = 2,  additional = 0                                                                                                                                                                                                   
                                                                                                                                                                                                                                                                               
    QUESTIONS:                                                                                                                                                                                                                                                                 
        roo.ee, type = SOA, class = IN                                                                                                                                                                                                                                         
    ANSWERS:                                                                                                                                                                                                                                                                   
    ->  roo.ee                                                                                                                                                                                                                                                                 
        ttl = 13889 (3 hours 51 mins 29 secs)                                                                                                                                                                                                                                  
        primary name server = ns1.dbweb.ee                                                                                                                                                                                                                                     
        responsible mail addr = hostmaster.roo.ee                                                                                                                                                                                                                              
        serial  = 2017102701                                                                                                                                                                                                                                                   
        refresh = 14400 (4 hours)                                                                                                                                                                                                                                              
        retry   = 3600 (1 hour)                                                                                                                                                                                                                                                
        expire  = 1209600 (14 days)                                                                                                                                                                                                                                            
        default TTL = 86400 (1 day)                                                                                                                                                                                                                                            
    AUTHORITY RECORDS:                                                                                                                                                                                                                                                         
    ->  roo.ee                                                                                                                                                                                                                                                                 
        nameserver = ns1.dbweb.ee                                                                                                                                                                                                                                              
        ttl = 3272 (54 mins 32 secs)                                                                                                                                                                                                                                           
    ->  roo.ee                                                                                                                                                                                                                                                                 
        nameserver = ns2.dbweb.ee                                                                                                                                                                                                                                              
        ttl = 3272 (54 mins 32 secs)                                                                                                                                                                                                                                           
                                                                                                                                                                                                                                                                               
------------                                                                                                                                                                                                                                                                   
roo.ee                                                                                                                                                                                                                                                                         
        ttl = 13889 (3 hours 51 mins 29 secs)                                                                                                                                                                                                                                  
        primary name server = ns1.dbweb.ee                                                                                                                                                                                                                                     
        responsible mail addr = hostmaster.roo.ee                                                                                                                                                                                                                              
        serial  = 2017102701                                                                                                                                                                                                                                                   
        refresh = 14400 (4 hours)                                                                                                                                                                                                                                              
        retry   = 3600 (1 hour)                                                                                                                                                                                                                                                
        expire  = 1209600 (14 days)                                                                                                                                                                                                                                            
        default TTL = 86400 (1 day)                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                               
roo.ee                                                                                                                                                                                                                                                                         
        nameserver = ns1.dbweb.ee                                                                                                                                                                                                                                              
        ttl = 3272 (54 mins 32 secs)                                                                                                                                                                                                                                           
roo.ee                                                                                                                                                                                                                                                                         
        nameserver = ns2.dbweb.ee                                                                                                                                                                                                                                              
        ttl = 3272 (54 mins 32 secs)                                                                                                                                                                                                                                           

Found a nice picture explains very well differences between symmetric encryption versus asymmetric encryption

https://medium.com/@peterchang_82818/review-3-main-types-of-encryption-hash-symmetric-asymmetric-tutorial-example-understand-5e57c290324c

Nüüd kus mul on 1MHz colpitts signaali generaator valmis tuleks genereeritavat signaali hakata võimendama. Kogun siia power amplifier (PA) kohta informatsiooni.

Küsimused, millele ma praegu vastust otsin:

• Kui suur on hetkel signaaligeneraatrori väljundvõimsus?
• Mul on ilmselt vaja kõik komponendid varjestada
• Millist antenni ma vajan?

Hea video PA kohta

https://www.electronics-tutorials.ws/amplifier/amp_1.html

When you look at the winds aloft report the wind direction usually varies at 3, 6, 9, and 12 thousand feet. Average the wind direction from the winds aloft report and the surface wind. Use that average as a guide. Example:

Altitude	Direction
Surface	240
3000	260
6000	270
9000	270
12000	290

1330 / 5 = 266 Degree

Freefall Drift=Average wind during freefall/duration of freefall x 5280 feet

Example:

Altitude	Velocity(knots)
3000	15
6000	22
9000	28
12000	35

100 / 4 = 25 knots25 knots/60 seconds x 5280 feet = 2,165 feetRounded to 2,000 feet of approximate Freefall Drift

Software: Hortonworks HDF

OS: RHEL 7.x

Set up two Schema Registries. Modified schema registries configuration in a way that Kerberos SPN are similar. Defaul Ambari set up SPN as SERVICE/FQDN@REALM.

Set up AWS ELB.

When requesting a resource I got on success response and one Error 403 GSSException: Failure unspecified at GSS-API level (Mechanism level: Checksum failed)

After shut down one schema registry turned out all request were ok, so second schema registry responded every time GSSException: Failure unspecified at GSS-API level (Mechanism level: Checksum failed)

Used kvno for debugging

In first server:

[root@ip-10-113-86-26 ~]# kvno -k /etc/security/keytabs/spnego.service.keytab HTTP/registry.dp.example.net
HTTP/registry.dp.example.net@DP.EXAMPLE.NET: kvno = 3, keytab entry valid

In second server:

[root@ip-10-113-86-4 ~]# kvno -k /etc/security/keytabs/spnego.service.keytab HTTP/registry.dp.example.net
HTTP/registry.dp.example.net@DP.EXAMPLE.NET: kvno = 3, keytab entry invalid

[root@ip-10-113-86-4 ~]# klist -kte /etc/security/keytabs/spnego.service.keytab
Keytab name: FILE:/etc/security/keytabs/spnego.service.keytab
KVNO Timestamp Principal
—- ——————- ——————————————————
2 05/22/2019 13:56:14 HTTP/ip-10-113-86-4.eu-central-1.compute.internal@DP.EXAMPLE.NET (aes128-cts-hmac-sha1-96)
2 05/22/2019 13:56:14 HTTP/ip-10-113-86-4.eu-central-1.compute.internal@DP.EXAMPLE.NET (aes256-cts-hmac-sha1-96)
2 05/22/2019 13:56:14 HTTP/ip-10-113-86-4.eu-central-1.compute.internal@DP.EXAMPLE.NET (arcfour-hmac)
2 05/22/2019 13:56:14 HTTP/ip-10-113-86-4.eu-central-1.compute.internal@DP.EXAMPLE.NET (des3-cbc-sha1)
2 05/22/2019 13:56:14 HTTP/ip-10-113-86-4.eu-central-1.compute.internal@DP.EXAMPLE.NET (des-cbc-md5)
2 05/22/2019 14:16:11 HTTP/registry.dp.example.net@DP.EXAMPLE.NET (aes256-cts-hmac-sha1-96)
2 05/22/2019 14:16:11 HTTP/registry.dp.example.net@DP.EXAMPLE.NET (aes128-cts-hmac-sha1-96)

[root@ip-10-113-86-4 ~]# kadmin -s 10.113.86.28 -p admin/admin
Authenticating as principal admin/admin with password.
Password for admin/admin@DP.EXAMPLE.NET:
kadmin: getprinc HTTP/registry.dp.example.net@DP.EXAMPLE.NET
Principal: HTTP/registry.dp.example.net@DP.EXAMPLE.NET
Expiration date: [never]
Last password change: Wed May 22 14:16:48 UTC 2019
Password expiration date: [never]
Maximum ticket life: 1 day 00:00:00
Maximum renewable life: 0 days 00:00:00
Last modified: Wed May 22 14:16:48 UTC 2019 (admin/admin@DP.EXAMPLE.NET)
Last successful authentication: [never]
Last failed authentication: [never]
Failed password attempts: 0
Number of keys: 2
Key: vno 3, aes256-cts-hmac-sha1-96
Key: vno 3, aes128-cts-hmac-sha1-96
MKey: vno 1
Attributes:
Policy: [none]
kadmin:

The problem is that in case you use kadmin ktadd it will increase printcipal KVO

I have always problem how to know where defined variables I can see via Ambari GUI – {{ some text }}

First this pattern is called Jinja Template framework

Lets learn via example

I have HDF schema registry and I don’t like in example kerberos.principal value Ambari puts there HTTP/[hostname]@REALM. I put two schema registries behind AWS EBL and I need static SPN.

Jinja template is found /var/lib/ambari-agent/cache/common-services/REGISTRY/0.3.0/package/templates/registry.yaml.j2

From template I can find {{registry_ui_jaas_principal}}

Ambari uses lots of params.py files to generate variables. The one I am interested in is /var/lib/ambari-agent/cache/common-services/REGISTRY/0.3.0/package/scripts/params.py and it is copy of /var/lib/ambari-server/resources/mpacks/hdf-ambari-mpack-3.3.1.0-10/common-services/REGISTRY/0.3.0/package/scripts/params.py

Do not change file under cache because after ambari restart static one will overwrites this so change
/var/lib/ambari-server/resources/mpacks/hdf-ambari-mpack-3.3.1.0-10/common-services/REGISTRY/0.3.0/package/scripts/params.py